openssh/serverloop.c

   1 /* $OpenBSD: serverloop.c,v 1.153 2008/06/30 12:15:39 djm Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * Server main loop for handling the interactive session.
   7  *
   8  * As far as I am concerned, the code I have written for this software
   9  * can be used freely for any purpose.  Any derived versions of this
  10  * software must be clearly marked as such, and if the derived work is
  11  * incompatible with the protocol description in the RFC file, it must be
  12  * called by a name other than "ssh" or "Secure Shell".
  13  *
  14  * SSH2 support by Markus Friedl.
  15  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  16  *
  17  * Redistribution and use in source and binary forms, with or without
  18  * modification, are permitted provided that the following conditions
  19  * are met:
  20  * 1. Redistributions of source code must retain the above copyright
  21  *    notice, this list of conditions and the following disclaimer.
  22  * 2. Redistributions in binary form must reproduce the above copyright
  23  *    notice, this list of conditions and the following disclaimer in the
  24  *    documentation and/or other materials provided with the distribution.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  27  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  28  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  29  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  30  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  31  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  35  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 #include "includes.h"
  39
  40 #include <sys/types.h>
  41 #include <sys/param.h>
  42 #include <sys/wait.h>
  43 #include <sys/socket.h>
  44 #ifdef HAVE_SYS_TIME_H
  45 # include <sys/time.h>
  46 #endif
  47
  48 #include <netinet/in.h>
  49
  50 #include <errno.h>
  51 #include <fcntl.h>
  52 #include <pwd.h>
  53 #include <signal.h>
  54 #include <string.h>
  55 #include <termios.h>
  56 #include <unistd.h>
  57 #include <stdarg.h>
  58
  59 #include "openbsd-compat/sys-queue.h"
  60 #include "xmalloc.h"
  61 #include "packet.h"
  62 #include "buffer.h"
  63 #include "log.h"
  64 #include "servconf.h"
  65 #include "canohost.h"
  66 #include "sshpty.h"
  67 #include "channels.h"
  68 #include "compat.h"
  69 #include "ssh1.h"
  70 #include "ssh2.h"
  71 #include "key.h"
  72 #include "cipher.h"
  73 #include "kex.h"
  74 #include "hostfile.h"
  75 #include "auth.h"
  76 #include "session.h"
  77 #include "dispatch.h"
  78 #include "auth-options.h"
  79 #include "serverloop.h"
  80 #include "misc.h"
  81
  82 extern ServerOptions options;
  83
  84 /* XXX */
  85 extern Kex *xxx_kex;
  86 extern Authctxt *the_authctxt;
  87 extern int use_privsep;
  88
  89 static Buffer stdin_buffer;     /* Buffer for stdin data. */
  90 static Buffer stdout_buffer;    /* Buffer for stdout data. */
  91 static Buffer stderr_buffer;    /* Buffer for stderr data. */
  92 static int fdin;                /* Descriptor for stdin (for writing) */
  93 static int fdout;               /* Descriptor for stdout (for reading);
  94                                    May be same number as fdin. */
  95 static int fderr;               /* Descriptor for stderr.  May be -1. */
  96 static u_long stdin_bytes = 0;  /* Number of bytes written to stdin. */
  97 static u_long stdout_bytes = 0; /* Number of stdout bytes sent to client. */
  98 static u_long stderr_bytes = 0; /* Number of stderr bytes sent to client. */
  99 static u_long fdout_bytes = 0;  /* Number of stdout bytes read from program. */
 100 static int stdin_eof = 0;       /* EOF message received from client. */
 101 static int fdout_eof = 0;       /* EOF encountered reading from fdout. */
 102 static int fderr_eof = 0;       /* EOF encountered readung from fderr. */
 103 static int fdin_is_tty = 0;     /* fdin points to a tty. */
 104 static int connection_in;       /* Connection to client (input). */
 105 static int connection_out;      /* Connection to client (output). */
 106 static int connection_closed = 0;       /* Connection to client closed. */
 107 static u_int buffer_high;       /* "Soft" max buffer size. */
 108 static int no_more_sessions = 0; /* Disallow further sessions. */
 109
 110 /*
 111  * This SIGCHLD kludge is used to detect when the child exits.  The server
 112  * will exit after that, as soon as forwarded connections have terminated.
 113  */
 114
 115 static volatile sig_atomic_t child_terminated = 0;      /* The child has terminated. */
 116
 117 /* Cleanup on signals (!use_privsep case only) */
 118 static volatile sig_atomic_t received_sigterm = 0;
 119
 120 /* prototypes */
 121 static void server_init_dispatch(void);
 122
 123 /*
 124  * Returns current time in seconds from Jan 1, 1970 with the maximum
 125  * available resolution.
 126  */
 127
 128 static double
 129 get_current_time(void)
 130 {
 131         struct timeval tv;
 132         gettimeofday(&tv, NULL);
 133         return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
 134 }
 135
 136
 137 /*
 138  * we write to this pipe if a SIGCHLD is caught in order to avoid
 139  * the race between select() and child_terminated
 140  */
 141 static int notify_pipe[2];
 142 static void
 143 notify_setup(void)
 144 {
 145         if (pipe(notify_pipe) < 0) {
 146                 error("pipe(notify_pipe) failed %s", strerror(errno));
 147         } else if ((fcntl(notify_pipe[0], F_SETFD, 1) == -1) ||
 148             (fcntl(notify_pipe[1], F_SETFD, 1) == -1)) {
 149                 error("fcntl(notify_pipe, F_SETFD) failed %s", strerror(errno));
 150                 close(notify_pipe[0]);
 151                 close(notify_pipe[1]);
 152         } else {
 153                 set_nonblock(notify_pipe[0]);
 154                 set_nonblock(notify_pipe[1]);
 155                 return;
 156         }
 157         notify_pipe[0] = -1;    /* read end */
 158         notify_pipe[1] = -1;    /* write end */
 159 }
 160 static void
 161 notify_parent(void)
 162 {
 163         if (notify_pipe[1] != -1)
 164                 write(notify_pipe[1], "", 1);
 165 }
 166 static void
 167 notify_prepare(fd_set *readset)
 168 {
 169         if (notify_pipe[0] != -1)
 170                 FD_SET(notify_pipe[0], readset);
 171 }
 172 static void
 173 notify_done(fd_set *readset)
 174 {
 175         char c;
 176
 177         if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset))
 178                 while (read(notify_pipe[0], &c, 1) != -1)
 179                         debug2("notify_done: reading");
 180 }
 181
 182 /*ARGSUSED*/
 183 static void
 184 sigchld_handler(int sig)
 185 {
 186         int save_errno = errno;
 187         child_terminated = 1;
 188 #ifndef _UNICOS
 189         mysignal(SIGCHLD, sigchld_handler);
 190 #endif
 191         notify_parent();
 192         errno = save_errno;
 193 }
 194
 195 /*ARGSUSED*/
 196 static void
 197 sigterm_handler(int sig)
 198 {
 199         received_sigterm = sig;
 200 }
 201
 202 /*
 203  * Make packets from buffered stderr data, and buffer it for sending
 204  * to the client.
 205  */
 206 static void
 207 make_packets_from_stderr_data(void)
 208 {
 209         u_int len;
 210
 211         /* Send buffered stderr data to the client. */
 212         while (buffer_len(&stderr_buffer) > 0 &&
 213             packet_not_very_much_data_to_write()) {
 214                 len = buffer_len(&stderr_buffer);
 215                 if (packet_is_interactive()) {
 216                         if (len > 512)
 217                                 len = 512;
 218                 } else {
 219                         /* Keep the packets at reasonable size. */
 220                         if (len > packet_get_maxsize())
 221                                 len = packet_get_maxsize();
 222                 }
 223                 packet_start(SSH_SMSG_STDERR_DATA);
 224                 packet_put_string(buffer_ptr(&stderr_buffer), len);
 225                 packet_send();
 226                 buffer_consume(&stderr_buffer, len);
 227                 stderr_bytes += len;
 228         }
 229 }
 230
 231 /*
 232  * Make packets from buffered stdout data, and buffer it for sending to the
 233  * client.
 234  */
 235 static void
 236 make_packets_from_stdout_data(void)
 237 {
 238         u_int len;
 239
 240         /* Send buffered stdout data to the client. */
 241         while (buffer_len(&stdout_buffer) > 0 &&
 242             packet_not_very_much_data_to_write()) {
 243                 len = buffer_len(&stdout_buffer);
 244                 if (packet_is_interactive()) {
 245                         if (len > 512)
 246                                 len = 512;
 247                 } else {
 248                         /* Keep the packets at reasonable size. */
 249                         if (len > packet_get_maxsize())
 250                                 len = packet_get_maxsize();
 251                 }
 252                 packet_start(SSH_SMSG_STDOUT_DATA);
 253                 packet_put_string(buffer_ptr(&stdout_buffer), len);
 254                 packet_send();
 255                 buffer_consume(&stdout_buffer, len);
 256                 stdout_bytes += len;
 257         }
 258 }
 259
 260 static void
 261 client_alive_check(void)
 262 {
 263         int channel_id;
 264
 265         /* timeout, check to see how many we have had */
 266         if (++keep_alive_timeouts > options.client_alive_count_max) {
 267                 logit("Timeout, client not responding.");
 268                 cleanup_exit(255);
 269         }
 270
 271         /*
 272          * send a bogus global/channel request with "wantreply",
 273          * we should get back a failure
 274          */
 275         if ((channel_id = channel_find_open()) == -1) {
 276                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
 277                 packet_put_cstring("keepalive@openssh.com");
 278                 packet_put_char(1);     /* boolean: want reply */
 279         } else {
 280                 channel_request_start(channel_id, "keepalive@openssh.com", 1);
 281         }
 282         packet_send();
 283 }
 284
 285 /*
 286  * Sleep in select() until we can do something.  This will initialize the
 287  * select masks.  Upon return, the masks will indicate which descriptors
 288  * have data or can accept data.  Optionally, a maximum time can be specified
 289  * for the duration of the wait (0 = infinite).
 290  */
 291 static void
 292 wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
 293     u_int *nallocp, u_int max_time_milliseconds)
 294 {
 295         struct timeval tv, *tvp;
 296         int ret;
 297         int client_alive_scheduled = 0;
 298         int program_alive_scheduled = 0;
 299
 300         /*
 301          * if using client_alive, set the max timeout accordingly,
 302          * and indicate that this particular timeout was for client
 303          * alive by setting the client_alive_scheduled flag.
 304          *
 305          * this could be randomized somewhat to make traffic
 306          * analysis more difficult, but we're not doing it yet.
 307          */
 308         if (compat20 &&
 309             max_time_milliseconds == 0 && options.client_alive_interval) {
 310                 client_alive_scheduled = 1;
 311                 max_time_milliseconds = options.client_alive_interval * 1000;
 312         }
 313
 314         /* Allocate and update select() masks for channel descriptors. */
 315         channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, 0);
 316
 317         if (compat20) {
 318 #if 0
 319                 /* wrong: bad condition XXX */
 320                 if (channel_not_very_much_buffered_data())
 321 #endif
 322                 FD_SET(connection_in, *readsetp);
 323         } else {
 324                 /*
 325                  * Read packets from the client unless we have too much
 326                  * buffered stdin or channel data.
 327                  */
 328                 if (buffer_len(&stdin_buffer) < buffer_high &&
 329                     channel_not_very_much_buffered_data())
 330                         FD_SET(connection_in, *readsetp);
 331                 /*
 332                  * If there is not too much data already buffered going to
 333                  * the client, try to get some more data from the program.
 334                  */
 335                 if (packet_not_very_much_data_to_write()) {
 336                         program_alive_scheduled = child_terminated;
 337                         if (!fdout_eof)
 338                                 FD_SET(fdout, *readsetp);
 339                         if (!fderr_eof)
 340                                 FD_SET(fderr, *readsetp);
 341                 }
 342                 /*
 343                  * If we have buffered data, try to write some of that data
 344                  * to the program.
 345                  */
 346                 if (fdin != -1 && buffer_len(&stdin_buffer) > 0)
 347                         FD_SET(fdin, *writesetp);
 348         }
 349         notify_prepare(*readsetp);
 350
 351         /*
 352          * If we have buffered packet data going to the client, mark that
 353          * descriptor.
 354          */
 355         if (packet_have_data_to_write())
 356                 FD_SET(connection_out, *writesetp);
 357
 358         /*
 359          * If child has terminated and there is enough buffer space to read
 360          * from it, then read as much as is available and exit.
 361          */
 362         if (child_terminated && packet_not_very_much_data_to_write())
 363                 if (max_time_milliseconds == 0 || client_alive_scheduled)
 364                         max_time_milliseconds = 100;
 365
 366         if (max_time_milliseconds == 0)
 367                 tvp = NULL;
 368         else {
 369                 tv.tv_sec = max_time_milliseconds / 1000;
 370                 tv.tv_usec = 1000 * (max_time_milliseconds % 1000);
 371                 tvp = &tv;
 372         }
 373
 374         /* Wait for something to happen, or the timeout to expire. */
 375         ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
 376
 377         if (ret == -1) {
 378                 memset(*readsetp, 0, *nallocp);
 379                 memset(*writesetp, 0, *nallocp);
 380                 if (errno != EINTR)
 381                         error("select: %.100s", strerror(errno));
 382         } else {
 383                 if (ret == 0 && client_alive_scheduled)
 384                         client_alive_check();
 385                 if (!compat20 && program_alive_scheduled && fdin_is_tty) {
 386                         if (!fdout_eof)
 387                                 FD_SET(fdout, *readsetp);
 388                         if (!fderr_eof)
 389                                 FD_SET(fderr, *readsetp);
 390                 }
 391         }
 392
 393         notify_done(*readsetp);
 394 }
 395
 396 /*
 397  * Processes input from the client and the program.  Input data is stored
 398  * in buffers and processed later.
 399  */
 400 static void
 401 process_input(fd_set *readset)
 402 {
 403         int len;
 404         char buf[16384];
 405
 406         /* Read and buffer any input data from the client. */
 407         if (FD_ISSET(connection_in, readset)) {
 408                 len = read(connection_in, buf, sizeof(buf));
 409                 if (len == 0) {
 410                         verbose("Connection closed by %.100s",
 411                             get_remote_ipaddr());
 412                         connection_closed = 1;
 413                         if (compat20)
 414                                 return;
 415                         cleanup_exit(255);
 416                 } else if (len < 0) {
 417                         if (errno != EINTR && errno != EAGAIN &&
 418                             errno != EWOULDBLOCK) {
 419                                 verbose("Read error from remote host "
 420                                     "%.100s: %.100s",
 421                                     get_remote_ipaddr(), strerror(errno));
 422                                 cleanup_exit(255);
 423                         }
 424                 } else {
 425                         /* Buffer any received data. */
 426                         packet_process_incoming(buf, len);
 427                         fdout_bytes += len;
 428                 }
 429         }
 430         if (compat20)
 431                 return;
 432
 433         /* Read and buffer any available stdout data from the program. */
 434         if (!fdout_eof && FD_ISSET(fdout, readset)) {
 435                 errno = 0;
 436                 len = read(fdout, buf, sizeof(buf));
 437                 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
 438                     errno == EWOULDBLOCK) && !child_terminated))) {
 439                         /* do nothing */
 440 #ifndef PTY_ZEROREAD
 441                 } else if (len <= 0) {
 442 #else
 443                 } else if ((!isatty(fdout) && len <= 0) ||
 444                     (isatty(fdout) && (len < 0 || (len == 0 && errno != 0)))) {
 445 #endif
 446                         fdout_eof = 1;
 447                 } else {
 448                         buffer_append(&stdout_buffer, buf, len);
 449                         fdout_bytes += len;
 450                         debug ("FD out now: %ld", fdout_bytes);
 451                 }
 452         }
 453         /* Read and buffer any available stderr data from the program. */
 454         if (!fderr_eof && FD_ISSET(fderr, readset)) {
 455                 errno = 0;
 456                 len = read(fderr, buf, sizeof(buf));
 457                 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
 458                     errno == EWOULDBLOCK) && !child_terminated))) {
 459                         /* do nothing */
 460 #ifndef PTY_ZEROREAD
 461                 } else if (len <= 0) {
 462 #else
 463                 } else if ((!isatty(fderr) && len <= 0) ||
 464                     (isatty(fderr) && (len < 0 || (len == 0 && errno != 0)))) {
 465 #endif
 466                         fderr_eof = 1;
 467                 } else {
 468                         buffer_append(&stderr_buffer, buf, len);
 469                 }
 470         }
 471 }
 472
 473 /*
 474  * Sends data from internal buffers to client program stdin.
 475  */
 476 static void
 477 process_output(fd_set *writeset)
 478 {
 479         struct termios tio;
 480         u_char *data;
 481         u_int dlen;
 482         int len;
 483
 484         /* Write buffered data to program stdin. */
 485         if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
 486                 data = buffer_ptr(&stdin_buffer);
 487                 dlen = buffer_len(&stdin_buffer);
 488                 len = write(fdin, data, dlen);
 489                 if (len < 0 &&
 490                     (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) {
 491                         /* do nothing */
 492                 } else if (len <= 0) {
 493                         if (fdin != fdout)
 494                                 close(fdin);
 495                         else
 496                                 shutdown(fdin, SHUT_WR); /* We will no longer send. */
 497                         fdin = -1;
 498                 } else {
 499                         /* Successful write. */
 500                         if (fdin_is_tty && dlen >= 1 && data[0] != '\r' &&
 501                             tcgetattr(fdin, &tio) == 0 &&
 502                             !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
 503                                 /*
 504                                  * Simulate echo to reduce the impact of
 505                                  * traffic analysis
 506                                  */
 507                                 packet_send_ignore(len);
 508                                 packet_send();
 509                         }
 510                         /* Consume the data from the buffer. */
 511                         buffer_consume(&stdin_buffer, len);
 512                         /* Update the count of bytes written to the program. */
 513                         stdin_bytes += len;
 514                 }
 515         }
 516         /* Send any buffered packet data to the client. */
 517         if (FD_ISSET(connection_out, writeset))
 518                 stdin_bytes += packet_write_poll();
 519 }
 520
 521 /*
 522  * Wait until all buffered output has been sent to the client.
 523  * This is used when the program terminates.
 524  */
 525 static void
 526 drain_output(void)
 527 {
 528         /* Send any buffered stdout data to the client. */
 529         if (buffer_len(&stdout_buffer) > 0) {
 530                 packet_start(SSH_SMSG_STDOUT_DATA);
 531                 packet_put_string(buffer_ptr(&stdout_buffer),
 532                                   buffer_len(&stdout_buffer));
 533                 packet_send();
 534                 /* Update the count of sent bytes. */
 535                 stdout_bytes += buffer_len(&stdout_buffer);
 536         }
 537         /* Send any buffered stderr data to the client. */
 538         if (buffer_len(&stderr_buffer) > 0) {
 539                 packet_start(SSH_SMSG_STDERR_DATA);
 540                 packet_put_string(buffer_ptr(&stderr_buffer),
 541                                   buffer_len(&stderr_buffer));
 542                 packet_send();
 543                 /* Update the count of sent bytes. */
 544                 stderr_bytes += buffer_len(&stderr_buffer);
 545         }
 546         /* Wait until all buffered data has been written to the client. */
 547         packet_write_wait();
 548 }
 549
 550 static void
 551 process_buffered_input_packets(void)
 552 {
 553         dispatch_run(DISPATCH_NONBLOCK, NULL, compat20 ? xxx_kex : NULL);
 554 }
 555
 556 /*
 557  * Performs the interactive session.  This handles data transmission between
 558  * the client and the program.  Note that the notion of stdin, stdout, and
 559  * stderr in this function is sort of reversed: this function writes to
 560  * stdin (of the child program), and reads from stdout and stderr (of the
 561  * child program).
 562  */
 563 void
 564 server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
 565 {
 566         fd_set *readset = NULL, *writeset = NULL;
 567         int max_fd = 0;
 568         u_int nalloc = 0;
 569         int wait_status;        /* Status returned by wait(). */
 570         pid_t wait_pid;         /* pid returned by wait(). */
 571         int waiting_termination = 0;    /* Have displayed waiting close message. */
 572         u_int max_time_milliseconds;
 573         u_int previous_stdout_buffer_bytes;
 574         u_int stdout_buffer_bytes;
 575         int type;
 576
 577         debug("Entering interactive session.");
 578
 579         /* Initialize the SIGCHLD kludge. */
 580         child_terminated = 0;
 581         mysignal(SIGCHLD, sigchld_handler);
 582
 583         if (!use_privsep) {
 584                 signal(SIGTERM, sigterm_handler);
 585                 signal(SIGINT, sigterm_handler);
 586                 signal(SIGQUIT, sigterm_handler);
 587         }
 588
 589         /* Initialize our global variables. */
 590         fdin = fdin_arg;
 591         fdout = fdout_arg;
 592         fderr = fderr_arg;
 593
 594         /* nonblocking IO */
 595         set_nonblock(fdin);
 596         set_nonblock(fdout);
 597         /* we don't have stderr for interactive terminal sessions, see below */
 598         if (fderr != -1)
 599                 set_nonblock(fderr);
 600
 601         if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin))
 602                 fdin_is_tty = 1;
 603
 604         connection_in = packet_get_connection_in();
 605         connection_out = packet_get_connection_out();
 606
 607         notify_setup();
 608
 609         previous_stdout_buffer_bytes = 0;
 610
 611         /* Set approximate I/O buffer size. */
 612         if (packet_is_interactive())
 613                 buffer_high = 4096;
 614         else
 615                 buffer_high = 64 * 1024;
 616
 617 #if 0
 618         /* Initialize max_fd to the maximum of the known file descriptors. */
 619         max_fd = MAX(connection_in, connection_out);
 620         max_fd = MAX(max_fd, fdin);
 621         max_fd = MAX(max_fd, fdout);
 622         if (fderr != -1)
 623                 max_fd = MAX(max_fd, fderr);
 624 #endif
 625
 626         /* Initialize Initialize buffers. */
 627         buffer_init(&stdin_buffer);
 628         buffer_init(&stdout_buffer);
 629         buffer_init(&stderr_buffer);
 630
 631         /*
 632          * If we have no separate fderr (which is the case when we have a pty
 633          * - there we cannot make difference between data sent to stdout and
 634          * stderr), indicate that we have seen an EOF from stderr.  This way
 635          * we don't need to check the descriptor everywhere.
 636          */
 637         if (fderr == -1)
 638                 fderr_eof = 1;
 639
 640         server_init_dispatch();
 641
 642         /* Main loop of the server for the interactive session mode. */
 643         for (;;) {
 644
 645                 /* Process buffered packets from the client. */
 646                 process_buffered_input_packets();
 647
 648                 /*
 649                  * If we have received eof, and there is no more pending
 650                  * input data, cause a real eof by closing fdin.
 651                  */
 652                 if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) {
 653                         if (fdin != fdout)
 654                                 close(fdin);
 655                         else
 656                                 shutdown(fdin, SHUT_WR); /* We will no longer send. */
 657                         fdin = -1;
 658                 }
 659                 /* Make packets from buffered stderr data to send to the client. */
 660                 make_packets_from_stderr_data();
 661
 662                 /*
 663                  * Make packets from buffered stdout data to send to the
 664                  * client. If there is very little to send, this arranges to
 665                  * not send them now, but to wait a short while to see if we
 666                  * are getting more data. This is necessary, as some systems
 667                  * wake up readers from a pty after each separate character.
 668                  */
 669                 max_time_milliseconds = 0;
 670                 stdout_buffer_bytes = buffer_len(&stdout_buffer);
 671                 if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 &&
 672                     stdout_buffer_bytes != previous_stdout_buffer_bytes) {
 673                         /* try again after a while */
 674                         max_time_milliseconds = 10;
 675                 } else {
 676                         /* Send it now. */
 677                         make_packets_from_stdout_data();
 678                 }
 679                 previous_stdout_buffer_bytes = buffer_len(&stdout_buffer);
 680
 681                 /* Send channel data to the client. */
 682                 if (packet_not_very_much_data_to_write())
 683                         channel_output_poll();
 684
 685                 /*
 686                  * Bail out of the loop if the program has closed its output
 687                  * descriptors, and we have no more data to send to the
 688                  * client, and there is no pending buffered data.
 689                  */
 690                 if (fdout_eof && fderr_eof && !packet_have_data_to_write() &&
 691                     buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) {
 692                         if (!channel_still_open())
 693                                 break;
 694                         if (!waiting_termination) {
 695                                 const char *s = "Waiting for forwarded connections to terminate...\r\n";
 696                                 char *cp;
 697                                 waiting_termination = 1;
 698                                 buffer_append(&stderr_buffer, s, strlen(s));
 699
 700                                 /* Display list of open channels. */
 701                                 cp = channel_open_message();
 702                                 buffer_append(&stderr_buffer, cp, strlen(cp));
 703                                 xfree(cp);
 704                         }
 705                 }
 706                 max_fd = MAX(connection_in, connection_out);
 707                 max_fd = MAX(max_fd, fdin);
 708                 max_fd = MAX(max_fd, fdout);
 709                 max_fd = MAX(max_fd, fderr);
 710                 max_fd = MAX(max_fd, notify_pipe[0]);
 711
 712                 /* Sleep in select() until we can do something. */
 713                 wait_until_can_do_something(&readset, &writeset, &max_fd,
 714                     &nalloc, max_time_milliseconds);
 715
 716                 if (received_sigterm) {
 717                         logit("Exiting on signal %d", received_sigterm);
 718                         /* Clean up sessions, utmp, etc. */
 719                         cleanup_exit(255);
 720                 }
 721
 722                 /* Process any channel events. */
 723                 channel_after_select(readset, writeset);
 724
 725                 /* Process input from the client and from program stdout/stderr. */
 726                 process_input(readset);
 727
 728                 /* Process output to the client and to program stdin. */
 729                 process_output(writeset);
 730         }
 731         if (readset)
 732                 xfree(readset);
 733         if (writeset)
 734                 xfree(writeset);
 735
 736         /* Cleanup and termination code. */
 737
 738         /* Wait until all output has been sent to the client. */
 739         drain_output();
 740
 741         debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.",
 742             stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes);
 743
 744         /* Free and clear the buffers. */
 745         buffer_free(&stdin_buffer);
 746         buffer_free(&stdout_buffer);
 747         buffer_free(&stderr_buffer);
 748
 749         /* Close the file descriptors. */
 750         if (fdout != -1)
 751                 close(fdout);
 752         fdout = -1;
 753         fdout_eof = 1;
 754         if (fderr != -1)
 755                 close(fderr);
 756         fderr = -1;
 757         fderr_eof = 1;
 758         if (fdin != -1)
 759                 close(fdin);
 760         fdin = -1;
 761
 762         channel_free_all();
 763
 764         /* We no longer want our SIGCHLD handler to be called. */
 765         mysignal(SIGCHLD, SIG_DFL);
 766
 767         while ((wait_pid = waitpid(-1, &wait_status, 0)) < 0)
 768                 if (errno != EINTR)
 769                         packet_disconnect("wait: %.100s", strerror(errno));
 770         if (wait_pid != pid)
 771                 error("Strange, wait returned pid %ld, expected %ld",
 772                     (long)wait_pid, (long)pid);
 773
 774         /* Check if it exited normally. */
 775         if (WIFEXITED(wait_status)) {
 776                 /* Yes, normal exit.  Get exit status and send it to the client. */
 777                 debug("Command exited with status %d.", WEXITSTATUS(wait_status));
 778                 packet_start(SSH_SMSG_EXITSTATUS);
 779                 packet_put_int(WEXITSTATUS(wait_status));
 780                 packet_send();
 781                 packet_write_wait();
 782
 783                 /*
 784                  * Wait for exit confirmation.  Note that there might be
 785                  * other packets coming before it; however, the program has
 786                  * already died so we just ignore them.  The client is
 787                  * supposed to respond with the confirmation when it receives
 788                  * the exit status.
 789                  */
 790                 do {
 791                         type = packet_read();
 792                 }
 793                 while (type != SSH_CMSG_EXIT_CONFIRMATION);
 794
 795                 debug("Received exit confirmation.");
 796                 return;
 797         }
 798         /* Check if the program terminated due to a signal. */
 799         if (WIFSIGNALED(wait_status))
 800                 packet_disconnect("Command terminated on signal %d.",
 801                                   WTERMSIG(wait_status));
 802
 803         /* Some weird exit cause.  Just exit. */
 804         packet_disconnect("wait returned status %04x.", wait_status);
 805         /* NOTREACHED */
 806 }
 807
 808 static void
 809 collect_children(void)
 810 {
 811         pid_t pid;
 812         sigset_t oset, nset;
 813         int status;
 814
 815         /* block SIGCHLD while we check for dead children */
 816         sigemptyset(&nset);
 817         sigaddset(&nset, SIGCHLD);
 818         sigprocmask(SIG_BLOCK, &nset, &oset);
 819         if (child_terminated) {
 820                 debug("Received SIGCHLD.");
 821                 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
 822                     (pid < 0 && errno == EINTR))
 823                         if (pid > 0)
 824                                 session_close_by_pid(pid, status);
 825                 child_terminated = 0;
 826         }
 827         sigprocmask(SIG_SETMASK, &oset, NULL);
 828 }
 829
 830 void
 831 server_loop2(Authctxt *authctxt)
 832 {
 833         fd_set *readset = NULL, *writeset = NULL;
 834         int rekeying = 0, max_fd, nalloc = 0;
 835         double start_time, total_time;
 836
 837         debug("Entering interactive session for SSH2.");
 838         start_time = get_current_time();
 839
 840         mysignal(SIGCHLD, sigchld_handler);
 841         child_terminated = 0;
 842         connection_in = packet_get_connection_in();
 843         connection_out = packet_get_connection_out();
 844
 845         if (!use_privsep) {
 846                 signal(SIGTERM, sigterm_handler);
 847                 signal(SIGINT, sigterm_handler);
 848                 signal(SIGQUIT, sigterm_handler);
 849         }
 850
 851         notify_setup();
 852
 853         max_fd = MAX(connection_in, connection_out);
 854         max_fd = MAX(max_fd, notify_pipe[0]);
 855
 856         server_init_dispatch();
 857
 858         for (;;) {
 859                 process_buffered_input_packets();
 860
 861                 rekeying = (xxx_kex != NULL && !xxx_kex->done);
 862
 863                 if (!rekeying && packet_not_very_much_data_to_write())
 864                         channel_output_poll();
 865                 wait_until_can_do_something(&readset, &writeset, &max_fd,
 866                     &nalloc, 0);
 867
 868                 if (received_sigterm) {
 869                         logit("Exiting on signal %d", received_sigterm);
 870                         /* Clean up sessions, utmp, etc. */
 871                         cleanup_exit(255);
 872                 }
 873
 874                 collect_children();
 875                 if (!rekeying) {
 876                         channel_after_select(readset, writeset);
 877                         if (packet_need_rekeying()) {
 878                                 debug("need rekeying");
 879                                 xxx_kex->done = 0;
 880                                 kex_send_kexinit(xxx_kex);
 881                         }
 882                 }
 883                 process_input(readset);
 884                 if (connection_closed)
 885                         break;
 886                 process_output(writeset);
 887         }
 888         collect_children();
 889
 890         if (readset)
 891                 xfree(readset);
 892         if (writeset)
 893                 xfree(writeset);
 894
 895         /* free all channels, no more reads and writes */
 896         channel_free_all();
 897
 898         /* free remaining sessions, e.g. remove wtmp entries */
 899         session_destroy_all(NULL);
 900         total_time = get_current_time() - start_time;
 901         logit("SSH: Server;LType: Throughput;Remote: %s-%d;IN: %lu;OUT: %lu;Duration: %.1f;tPut_in: %.1f;tPut_out: %.1f",
 902               get_remote_ipaddr(), get_remote_port(),
 903               stdin_bytes, fdout_bytes, total_time, stdin_bytes / total_time,
 904               fdout_bytes / total_time);
 905 }
 906
 907 static void
 908 server_input_keep_alive(int type, u_int32_t seq, void *ctxt)
 909 {
 910         debug("Got %d/%u for keepalive", type, seq);
 911         /*
 912          * reset timeout, since we got a sane answer from the client.
 913          * even if this was generated by something other than
 914          * the bogus CHANNEL_REQUEST we send for keepalives.
 915          */
 916         keep_alive_timeouts = 0;
 917 }
 918
 919 static void
 920 server_input_stdin_data(int type, u_int32_t seq, void *ctxt)
 921 {
 922         char *data;
 923         u_int data_len;
 924
 925         /* Stdin data from the client.  Append it to the buffer. */
 926         /* Ignore any data if the client has closed stdin. */
 927         if (fdin == -1)
 928                 return;
 929         data = packet_get_string(&data_len);
 930         packet_check_eom();
 931         buffer_append(&stdin_buffer, data, data_len);
 932         memset(data, 0, data_len);
 933         xfree(data);
 934 }
 935
 936 static void
 937 server_input_eof(int type, u_int32_t seq, void *ctxt)
 938 {
 939         /*
 940          * Eof from the client.  The stdin descriptor to the
 941          * program will be closed when all buffered data has
 942          * drained.
 943          */
 944         debug("EOF received for stdin.");
 945         packet_check_eom();
 946         stdin_eof = 1;
 947 }
 948
 949 static void
 950 server_input_window_size(int type, u_int32_t seq, void *ctxt)
 951 {
 952         u_int row = packet_get_int();
 953         u_int col = packet_get_int();
 954         u_int xpixel = packet_get_int();
 955         u_int ypixel = packet_get_int();
 956
 957         debug("Window change received.");
 958         packet_check_eom();
 959         if (fdin != -1)
 960                 pty_change_window_size(fdin, row, col, xpixel, ypixel);
 961 }
 962
 963 static Channel *
 964 server_request_direct_tcpip(void)
 965 {
 966         Channel *c;
 967         char *target, *originator;
 968         int target_port, originator_port;
 969
 970         target = packet_get_string(NULL);
 971         target_port = packet_get_int();
 972         originator = packet_get_string(NULL);
 973         originator_port = packet_get_int();
 974         packet_check_eom();
 975
 976         debug("server_request_direct_tcpip: originator %s port %d, target %s "
 977             "port %d", originator, originator_port, target, target_port);
 978
 979         /* XXX check permission */
 980         c = channel_connect_to(target, target_port,
 981             "direct-tcpip", "direct-tcpip");
 982
 983         xfree(originator);
 984         xfree(target);
 985
 986         return c;
 987 }
 988
 989 static Channel *
 990 server_request_tun(void)
 991 {
 992         Channel *c = NULL;
 993         int mode, tun;
 994         int sock;
 995
 996         mode = packet_get_int();
 997         switch (mode) {
 998         case SSH_TUNMODE_POINTOPOINT:
 999         case SSH_TUNMODE_ETHERNET:
1000                 break;
1001         default:
1002                 packet_send_debug("Unsupported tunnel device mode.");
1003                 return NULL;
1004         }
1005         if ((options.permit_tun & mode) == 0) {
1006                 packet_send_debug("Server has rejected tunnel device "
1007                     "forwarding");
1008                 return NULL;
1009         }
1010
1011         tun = packet_get_int();
1012         if (forced_tun_device != -1) {
1013                 if (tun != SSH_TUNID_ANY && forced_tun_device != tun)
1014                         goto done;
1015                 tun = forced_tun_device;
1016         }
1017         sock = tun_open(tun, mode);
1018         if (sock < 0)
1019                 goto done;
1020         if (options.hpn_disabled)
1021         c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1022             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1023         else
1024                 c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1025                     options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1026         c->datagram = 1;
1027 #if defined(SSH_TUN_FILTER)
1028         if (mode == SSH_TUNMODE_POINTOPOINT)
1029                 channel_register_filter(c->self, sys_tun_infilter,
1030                     sys_tun_outfilter, NULL, NULL);
1031 #endif
1032
1033  done:
1034         if (c == NULL)
1035                 packet_send_debug("Failed to open the tunnel device.");
1036         return c;
1037 }
1038
1039 static Channel *
1040 server_request_session(void)
1041 {
1042         Channel *c;
1043
1044         debug("input_session_request");
1045         packet_check_eom();
1046
1047         if (no_more_sessions) {
1048                 packet_disconnect("Possible attack: attempt to open a session "
1049                     "after additional sessions disabled");
1050         }
1051
1052         /*
1053          * A server session has no fd to read or write until a
1054          * CHANNEL_REQUEST for a shell is made, so we set the type to
1055          * SSH_CHANNEL_LARVAL.  Additionally, a callback for handling all
1056          * CHANNEL_REQUEST messages is registered.
1057          */
1058         c = channel_new("session", SSH_CHANNEL_LARVAL,
1059             -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
1060             0, "server-session", 1);
1061         if ((options.tcp_rcv_buf_poll) && (!options.hpn_disabled))
1062                 c->dynamic_window = 1;
1063         if (session_open(the_authctxt, c->self) != 1) {
1064                 debug("session open failed, free channel %d", c->self);
1065                 channel_free(c);
1066                 return NULL;
1067         }
1068         channel_register_cleanup(c->self, session_close_by_channel, 0);
1069         return c;
1070 }
1071
1072 static void
1073 server_input_channel_open(int type, u_int32_t seq, void *ctxt)
1074 {
1075         Channel *c = NULL;
1076         char *ctype;
1077         int rchan;
1078         u_int rmaxpack, rwindow, len;
1079
1080         ctype = packet_get_string(&len);
1081         rchan = packet_get_int();
1082         rwindow = packet_get_int();
1083         rmaxpack = packet_get_int();
1084
1085         debug("server_input_channel_open: ctype %s rchan %d win %d max %d",
1086             ctype, rchan, rwindow, rmaxpack);
1087
1088         if (strcmp(ctype, "session") == 0) {
1089                 c = server_request_session();
1090         } else if (strcmp(ctype, "direct-tcpip") == 0) {
1091                 c = server_request_direct_tcpip();
1092         } else if (strcmp(ctype, "tun@openssh.com") == 0) {
1093                 c = server_request_tun();
1094         }
1095         if (c != NULL) {
1096                 debug("server_input_channel_open: confirm %s", ctype);
1097                 c->remote_id = rchan;
1098                 c->remote_window = rwindow;
1099                 c->remote_maxpacket = rmaxpack;
1100                 if (c->type != SSH_CHANNEL_CONNECTING) {
1101                         packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1102                         packet_put_int(c->remote_id);
1103                         packet_put_int(c->self);
1104                         packet_put_int(c->local_window);
1105                         packet_put_int(c->local_maxpacket);
1106                         packet_send();
1107                 }
1108         } else {
1109                 debug("server_input_channel_open: failure %s", ctype);
1110                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1111                 packet_put_int(rchan);
1112                 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1113                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1114                         packet_put_cstring("open failed");
1115                         packet_put_cstring("");
1116                 }
1117                 packet_send();
1118         }
1119         xfree(ctype);
1120 }
1121
1122 static void
1123 server_input_global_request(int type, u_int32_t seq, void *ctxt)
1124 {
1125         char *rtype;
1126         int want_reply;
1127         int success = 0;
1128
1129         rtype = packet_get_string(NULL);
1130         want_reply = packet_get_char();
1131         debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
1132
1133         /* -R style forwarding */
1134         if (strcmp(rtype, "tcpip-forward") == 0) {
1135                 struct passwd *pw;
1136                 char *listen_address;
1137                 u_short listen_port;
1138
1139                 pw = the_authctxt->pw;
1140                 if (pw == NULL || !the_authctxt->valid)
1141                         fatal("server_input_global_request: no/invalid user");
1142                 listen_address = packet_get_string(NULL);
1143                 listen_port = (u_short)packet_get_int();
1144                 debug("server_input_global_request: tcpip-forward listen %s port %d",
1145                     listen_address, listen_port);
1146
1147                 /* check permissions */
1148                 if (!options.allow_tcp_forwarding ||
1149                     no_port_forwarding_flag
1150 #ifndef NO_IPPORT_RESERVED_CONCEPT
1151                     || (listen_port < IPPORT_RESERVED && pw->pw_uid != 0)
1152 #endif
1153                     ) {
1154                         success = 0;
1155                         packet_send_debug("Server has disabled port forwarding.");
1156                 } else {
1157                         /* Start listening on the port */
1158                         success = channel_setup_remote_fwd_listener(
1159                             listen_address, listen_port, options.gateway_ports);
1160                 }
1161                 xfree(listen_address);
1162         } else if (strcmp(rtype, "cancel-tcpip-forward") == 0) {
1163                 char *cancel_address;
1164                 u_short cancel_port;
1165
1166                 cancel_address = packet_get_string(NULL);
1167                 cancel_port = (u_short)packet_get_int();
1168                 debug("%s: cancel-tcpip-forward addr %s port %d", __func__,
1169                     cancel_address, cancel_port);
1170
1171                 success = channel_cancel_rport_listener(cancel_address,
1172                     cancel_port);
1173                 xfree(cancel_address);
1174         } else if (strcmp(rtype, "no-more-sessions@openssh.com") == 0) {
1175                 no_more_sessions = 1;
1176                 success = 1;
1177         }
1178         if (want_reply) {
1179                 packet_start(success ?
1180                     SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1181                 packet_send();
1182                 packet_write_wait();
1183         }
1184         xfree(rtype);
1185 }
1186
1187 static void
1188 server_input_channel_req(int type, u_int32_t seq, void *ctxt)
1189 {
1190         Channel *c;
1191         int id, reply, success = 0;
1192         char *rtype;
1193
1194         id = packet_get_int();
1195         rtype = packet_get_string(NULL);
1196         reply = packet_get_char();
1197
1198         debug("server_input_channel_req: channel %d request %s reply %d",
1199             id, rtype, reply);
1200
1201         if ((c = channel_lookup(id)) == NULL)
1202                 packet_disconnect("server_input_channel_req: "
1203                     "unknown channel %d", id);
1204         if (!strcmp(rtype, "eow@openssh.com")) {
1205                 packet_check_eom();
1206                 chan_rcvd_eow(c);
1207         } else if ((c->type == SSH_CHANNEL_LARVAL ||
1208             c->type == SSH_CHANNEL_OPEN) && strcmp(c->ctype, "session") == 0)
1209                 success = session_input_channel_req(c, rtype);
1210         if (reply) {
1211                 packet_start(success ?
1212                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1213                 packet_put_int(c->remote_id);
1214                 packet_send();
1215         }
1216         xfree(rtype);
1217 }
1218
1219 static void
1220 server_init_dispatch_20(void)
1221 {
1222         debug("server_init_dispatch_20");
1223         dispatch_init(&dispatch_protocol_error);
1224         dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1225         dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1226         dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1227         dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1228         dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open);
1229         dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1230         dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1231         dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &server_input_channel_req);
1232         dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1233         dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
1234         dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm);
1235         dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm);
1236         /* client_alive */
1237         dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &server_input_keep_alive);
1238         dispatch_set(SSH2_MSG_REQUEST_FAILURE, &server_input_keep_alive);
1239         /* rekeying */
1240         dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1241 }
1242 static void
1243 server_init_dispatch_13(void)
1244 {
1245         debug("server_init_dispatch_13");
1246         dispatch_init(NULL);
1247         dispatch_set(SSH_CMSG_EOF, &server_input_eof);
1248         dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data);
1249         dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size);
1250         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1251         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1252         dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1253         dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1254         dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1255         dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1256 }
1257 static void
1258 server_init_dispatch_15(void)
1259 {
1260         server_init_dispatch_13();
1261         debug("server_init_dispatch_15");
1262         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1263         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose);
1264 }
1265 static void
1266 server_init_dispatch(void)
1267 {
1268         if (compat20)
1269                 server_init_dispatch_20();
1270         else if (compat13)
1271                 server_init_dispatch_13();
1272         else
1273                 server_init_dispatch_15();
1274 }