crypto/openssh/serverloop.c

   1 /* $OpenBSD: serverloop.c,v 1.172 2014/07/15 15:54:14 millert 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 "misc.h"
  65 #include "servconf.h"
  66 #include "canohost.h"
  67 #include "sshpty.h"
  68 #include "channels.h"
  69 #include "compat.h"
  70 #include "ssh1.h"
  71 #include "ssh2.h"
  72 #include "key.h"
  73 #include "cipher.h"
  74 #include "kex.h"
  75 #include "hostfile.h"
  76 #include "auth.h"
  77 #include "session.h"
  78 #include "dispatch.h"
  79 #include "auth-options.h"
  80 #include "serverloop.h"
  81 #include "roaming.h"
  82
  83 extern ServerOptions options;
  84
  85 /* XXX */
  86 extern Kex *xxx_kex;
  87 extern Authctxt *the_authctxt;
  88 extern int use_privsep;
  89
  90 static Buffer stdin_buffer;     /* Buffer for stdin data. */
  91 static Buffer stdout_buffer;    /* Buffer for stdout data. */
  92 static Buffer stderr_buffer;    /* Buffer for stderr data. */
  93 static int fdin;                /* Descriptor for stdin (for writing) */
  94 static int fdout;               /* Descriptor for stdout (for reading);
  95                                    May be same number as fdin. */
  96 static int fderr;               /* Descriptor for stderr.  May be -1. */
  97 static u_long stdin_bytes = 0;  /* Number of bytes written to stdin. */
  98 static u_long stdout_bytes = 0; /* Number of stdout bytes sent to client. */
  99 static u_long stderr_bytes = 0; /* Number of stderr bytes sent to client. */
 100 static u_long fdout_bytes = 0;  /* Number of stdout bytes read from program. */
 101 static int stdin_eof = 0;       /* EOF message received from client. */
 102 static int fdout_eof = 0;       /* EOF encountered reading from fdout. */
 103 static int fderr_eof = 0;       /* EOF encountered readung from fderr. */
 104 static int fdin_is_tty = 0;     /* fdin points to a tty. */
 105 static int connection_in;       /* Connection to client (input). */
 106 static int connection_out;      /* Connection to client (output). */
 107 static int connection_closed = 0;       /* Connection to client closed. */
 108 static u_int buffer_high;       /* "Soft" max buffer size. */
 109 static int no_more_sessions = 0; /* Disallow further sessions. */
 110
 111 /*
 112  * This SIGCHLD kludge is used to detect when the child exits.  The server
 113  * will exit after that, as soon as forwarded connections have terminated.
 114  */
 115
 116 static volatile sig_atomic_t child_terminated = 0;      /* The child has terminated. */
 117
 118 /* Cleanup on signals (!use_privsep case only) */
 119 static volatile sig_atomic_t received_sigterm = 0;
 120
 121 /* prototypes */
 122 static void server_init_dispatch(void);
 123
 124 /*
 125  * Returns current time in seconds from Jan 1, 1970 with the maximum
 126  * available resolution.
 127  */
 128
 129 static double
 130 get_current_time(void)
 131 {
 132         struct timeval tv;
 133         gettimeofday(&tv, NULL);
 134         return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
 135 }
 136
 137
 138 /*
 139  * we write to this pipe if a SIGCHLD is caught in order to avoid
 140  * the race between select() and child_terminated
 141  */
 142 static int notify_pipe[2];
 143 static void
 144 notify_setup(void)
 145 {
 146         if (pipe(notify_pipe) < 0) {
 147                 error("pipe(notify_pipe) failed %s", strerror(errno));
 148         } else if ((fcntl(notify_pipe[0], F_SETFD, FD_CLOEXEC) == -1) ||
 149             (fcntl(notify_pipe[1], F_SETFD, FD_CLOEXEC) == -1)) {
 150                 error("fcntl(notify_pipe, F_SETFD) failed %s", strerror(errno));
 151                 close(notify_pipe[0]);
 152                 close(notify_pipe[1]);
 153         } else {
 154                 set_nonblock(notify_pipe[0]);
 155                 set_nonblock(notify_pipe[1]);
 156                 return;
 157         }
 158         notify_pipe[0] = -1;    /* read end */
 159         notify_pipe[1] = -1;    /* write end */
 160 }
 161 static void
 162 notify_parent(void)
 163 {
 164         if (notify_pipe[1] != -1)
 165                 (void)write(notify_pipe[1], "", 1);
 166 }
 167 static void
 168 notify_prepare(fd_set *readset)
 169 {
 170         if (notify_pipe[0] != -1)
 171                 FD_SET(notify_pipe[0], readset);
 172 }
 173 static void
 174 notify_done(fd_set *readset)
 175 {
 176         char c;
 177
 178         if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset))
 179                 while (read(notify_pipe[0], &c, 1) != -1)
 180                         debug2("notify_done: reading");
 181 }
 182
 183 /*ARGSUSED*/
 184 static void
 185 sigchld_handler(int sig)
 186 {
 187         int save_errno = errno;
 188         child_terminated = 1;
 189 #ifndef _UNICOS
 190         mysignal(SIGCHLD, sigchld_handler);
 191 #endif
 192         notify_parent();
 193         errno = save_errno;
 194 }
 195
 196 /*ARGSUSED*/
 197 static void
 198 sigterm_handler(int sig)
 199 {
 200         received_sigterm = sig;
 201 }
 202
 203 /*
 204  * Make packets from buffered stderr data, and buffer it for sending
 205  * to the client.
 206  */
 207 static void
 208 make_packets_from_stderr_data(void)
 209 {
 210         u_int len;
 211
 212         /* Send buffered stderr data to the client. */
 213         while (buffer_len(&stderr_buffer) > 0 &&
 214             packet_not_very_much_data_to_write()) {
 215                 len = buffer_len(&stderr_buffer);
 216                 if (packet_is_interactive()) {
 217                         if (len > 512)
 218                                 len = 512;
 219                 } else {
 220                         /* Keep the packets at reasonable size. */
 221                         if (len > packet_get_maxsize())
 222                                 len = packet_get_maxsize();
 223                 }
 224                 packet_start(SSH_SMSG_STDERR_DATA);
 225                 packet_put_string(buffer_ptr(&stderr_buffer), len);
 226                 packet_send();
 227                 buffer_consume(&stderr_buffer, len);
 228                 stderr_bytes += len;
 229         }
 230 }
 231
 232 /*
 233  * Make packets from buffered stdout data, and buffer it for sending to the
 234  * client.
 235  */
 236 static void
 237 make_packets_from_stdout_data(void)
 238 {
 239         u_int len;
 240
 241         /* Send buffered stdout data to the client. */
 242         while (buffer_len(&stdout_buffer) > 0 &&
 243             packet_not_very_much_data_to_write()) {
 244                 len = buffer_len(&stdout_buffer);
 245                 if (packet_is_interactive()) {
 246                         if (len > 512)
 247                                 len = 512;
 248                 } else {
 249                         /* Keep the packets at reasonable size. */
 250                         if (len > packet_get_maxsize())
 251                                 len = packet_get_maxsize();
 252                 }
 253                 packet_start(SSH_SMSG_STDOUT_DATA);
 254                 packet_put_string(buffer_ptr(&stdout_buffer), len);
 255                 packet_send();
 256                 buffer_consume(&stdout_buffer, len);
 257                 stdout_bytes += len;
 258         }
 259 }
 260
 261 static void
 262 client_alive_check(void)
 263 {
 264         int channel_id;
 265
 266         /* timeout, check to see how many we have had */
 267         if (packet_inc_alive_timeouts() > options.client_alive_count_max) {
 268                 logit("Timeout, client not responding.");
 269                 cleanup_exit(255);
 270         }
 271
 272         /*
 273          * send a bogus global/channel request with "wantreply",
 274          * we should get back a failure
 275          */
 276         if ((channel_id = channel_find_open()) == -1) {
 277                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
 278                 packet_put_cstring("keepalive@openssh.com");
 279                 packet_put_char(1);     /* boolean: want reply */
 280         } else {
 281                 channel_request_start(channel_id, "keepalive@openssh.com", 1);
 282         }
 283         packet_send();
 284 }
 285
 286 /*
 287  * Sleep in select() until we can do something.  This will initialize the
 288  * select masks.  Upon return, the masks will indicate which descriptors
 289  * have data or can accept data.  Optionally, a maximum time can be specified
 290  * for the duration of the wait (0 = infinite).
 291  */
 292 static void
 293 wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
 294     u_int *nallocp, u_int64_t max_time_milliseconds)
 295 {
 296         struct timeval tv, *tvp;
 297         int ret;
 298         time_t minwait_secs = 0;
 299         int client_alive_scheduled = 0;
 300         int program_alive_scheduled = 0;
 301
 302         /* Allocate and update select() masks for channel descriptors. */
 303         channel_prepare_select(readsetp, writesetp, maxfdp, nallocp,
 304             &minwait_secs, 0);
 305
 306         if (minwait_secs != 0)
 307                 max_time_milliseconds = MIN(max_time_milliseconds,
 308                     (u_int)minwait_secs * 1000);
 309
 310         /*
 311          * if using client_alive, set the max timeout accordingly,
 312          * and indicate that this particular timeout was for client
 313          * alive by setting the client_alive_scheduled flag.
 314          *
 315          * this could be randomized somewhat to make traffic
 316          * analysis more difficult, but we're not doing it yet.
 317          */
 318         if (compat20 &&
 319             max_time_milliseconds == 0 && options.client_alive_interval) {
 320                 client_alive_scheduled = 1;
 321                 max_time_milliseconds =
 322                     (u_int64_t)options.client_alive_interval * 1000;
 323         }
 324
 325         if (compat20) {
 326 #if 0
 327                 /* wrong: bad condition XXX */
 328                 if (channel_not_very_much_buffered_data())
 329 #endif
 330                 FD_SET(connection_in, *readsetp);
 331         } else {
 332                 /*
 333                  * Read packets from the client unless we have too much
 334                  * buffered stdin or channel data.
 335                  */
 336                 if (buffer_len(&stdin_buffer) < buffer_high &&
 337                     channel_not_very_much_buffered_data())
 338                         FD_SET(connection_in, *readsetp);
 339                 /*
 340                  * If there is not too much data already buffered going to
 341                  * the client, try to get some more data from the program.
 342                  */
 343                 if (packet_not_very_much_data_to_write()) {
 344                         program_alive_scheduled = child_terminated;
 345                         if (!fdout_eof)
 346                                 FD_SET(fdout, *readsetp);
 347                         if (!fderr_eof)
 348                                 FD_SET(fderr, *readsetp);
 349                 }
 350                 /*
 351                  * If we have buffered data, try to write some of that data
 352                  * to the program.
 353                  */
 354                 if (fdin != -1 && buffer_len(&stdin_buffer) > 0)
 355                         FD_SET(fdin, *writesetp);
 356         }
 357         notify_prepare(*readsetp);
 358
 359         /*
 360          * If we have buffered packet data going to the client, mark that
 361          * descriptor.
 362          */
 363         if (packet_have_data_to_write())
 364                 FD_SET(connection_out, *writesetp);
 365
 366         /*
 367          * If child has terminated and there is enough buffer space to read
 368          * from it, then read as much as is available and exit.
 369          */
 370         if (child_terminated && packet_not_very_much_data_to_write())
 371                 if (max_time_milliseconds == 0 || client_alive_scheduled)
 372                         max_time_milliseconds = 100;
 373
 374         if (max_time_milliseconds == 0)
 375                 tvp = NULL;
 376         else {
 377                 tv.tv_sec = max_time_milliseconds / 1000;
 378                 tv.tv_usec = 1000 * (max_time_milliseconds % 1000);
 379                 tvp = &tv;
 380         }
 381
 382         /* Wait for something to happen, or the timeout to expire. */
 383         ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
 384
 385         if (ret == -1) {
 386                 memset(*readsetp, 0, *nallocp);
 387                 memset(*writesetp, 0, *nallocp);
 388                 if (errno != EINTR)
 389                         error("select: %.100s", strerror(errno));
 390         } else {
 391                 if (ret == 0 && client_alive_scheduled)
 392                         client_alive_check();
 393                 if (!compat20 && program_alive_scheduled && fdin_is_tty) {
 394                         if (!fdout_eof)
 395                                 FD_SET(fdout, *readsetp);
 396                         if (!fderr_eof)
 397                                 FD_SET(fderr, *readsetp);
 398                 }
 399         }
 400
 401         notify_done(*readsetp);
 402 }
 403
 404 /*
 405  * Processes input from the client and the program.  Input data is stored
 406  * in buffers and processed later.
 407  */
 408 static void
 409 process_input(fd_set *readset)
 410 {
 411         int len;
 412         char buf[16384];
 413
 414         /* Read and buffer any input data from the client. */
 415         if (FD_ISSET(connection_in, readset)) {
 416                 int cont = 0;
 417                 len = roaming_read(connection_in, buf, sizeof(buf), &cont);
 418                 if (len == 0) {
 419                         if (cont)
 420                                 return;
 421                         verbose("Connection closed by %.100s",
 422                             get_remote_ipaddr());
 423                         connection_closed = 1;
 424                         if (compat20)
 425                                 return;
 426                         cleanup_exit(255);
 427                 } else if (len < 0) {
 428                         if (errno != EINTR && errno != EAGAIN &&
 429                             errno != EWOULDBLOCK) {
 430                                 verbose("Read error from remote host "
 431                                     "%.100s: %.100s",
 432                                     get_remote_ipaddr(), strerror(errno));
 433                                 cleanup_exit(255);
 434                         }
 435                 } else {
 436                         /* Buffer any received data. */
 437                         packet_process_incoming(buf, len);
 438                         fdout_bytes += len;
 439                 }
 440         }
 441         if (compat20)
 442                 return;
 443
 444         /* Read and buffer any available stdout data from the program. */
 445         if (!fdout_eof && FD_ISSET(fdout, readset)) {
 446                 errno = 0;
 447                 len = read(fdout, buf, sizeof(buf));
 448                 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
 449                     errno == EWOULDBLOCK) && !child_terminated))) {
 450                         /* do nothing */
 451 #ifndef PTY_ZEROREAD
 452                 } else if (len <= 0) {
 453 #else
 454                 } else if ((!isatty(fdout) && len <= 0) ||
 455                     (isatty(fdout) && (len < 0 || (len == 0 && errno != 0)))) {
 456 #endif
 457                         fdout_eof = 1;
 458                 } else {
 459                         buffer_append(&stdout_buffer, buf, len);
 460                         fdout_bytes += len;
 461                         debug ("FD out now: %ld", fdout_bytes);
 462                 }
 463         }
 464         /* Read and buffer any available stderr data from the program. */
 465         if (!fderr_eof && FD_ISSET(fderr, readset)) {
 466                 errno = 0;
 467                 len = read(fderr, buf, sizeof(buf));
 468                 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
 469                     errno == EWOULDBLOCK) && !child_terminated))) {
 470                         /* do nothing */
 471 #ifndef PTY_ZEROREAD
 472                 } else if (len <= 0) {
 473 #else
 474                 } else if ((!isatty(fderr) && len <= 0) ||
 475                     (isatty(fderr) && (len < 0 || (len == 0 && errno != 0)))) {
 476 #endif
 477                         fderr_eof = 1;
 478                 } else {
 479                         buffer_append(&stderr_buffer, buf, len);
 480                 }
 481         }
 482 }
 483
 484 /*
 485  * Sends data from internal buffers to client program stdin.
 486  */
 487 static void
 488 process_output(fd_set *writeset)
 489 {
 490         struct termios tio;
 491         u_char *data;
 492         u_int dlen;
 493         int len;
 494
 495         /* Write buffered data to program stdin. */
 496         if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
 497                 data = buffer_ptr(&stdin_buffer);
 498                 dlen = buffer_len(&stdin_buffer);
 499                 len = write(fdin, data, dlen);
 500                 if (len < 0 &&
 501                     (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) {
 502                         /* do nothing */
 503                 } else if (len <= 0) {
 504                         if (fdin != fdout)
 505                                 close(fdin);
 506                         else
 507                                 shutdown(fdin, SHUT_WR); /* We will no longer send. */
 508                         fdin = -1;
 509                 } else {
 510                         /* Successful write. */
 511                         if (fdin_is_tty && dlen >= 1 && data[0] != '\r' &&
 512                             tcgetattr(fdin, &tio) == 0 &&
 513                             !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
 514                                 /*
 515                                  * Simulate echo to reduce the impact of
 516                                  * traffic analysis
 517                                  */
 518                                 packet_send_ignore(len);
 519                                 packet_send();
 520                         }
 521                         /* Consume the data from the buffer. */
 522                         buffer_consume(&stdin_buffer, len);
 523                         /* Update the count of bytes written to the program. */
 524                         stdin_bytes += len;
 525                 }
 526         }
 527         /* Send any buffered packet data to the client. */
 528         if (FD_ISSET(connection_out, writeset))
 529                 stdin_bytes += packet_write_poll();
 530 }
 531
 532 /*
 533  * Wait until all buffered output has been sent to the client.
 534  * This is used when the program terminates.
 535  */
 536 static void
 537 drain_output(void)
 538 {
 539         /* Send any buffered stdout data to the client. */
 540         if (buffer_len(&stdout_buffer) > 0) {
 541                 packet_start(SSH_SMSG_STDOUT_DATA);
 542                 packet_put_string(buffer_ptr(&stdout_buffer),
 543                                   buffer_len(&stdout_buffer));
 544                 packet_send();
 545                 /* Update the count of sent bytes. */
 546                 stdout_bytes += buffer_len(&stdout_buffer);
 547         }
 548         /* Send any buffered stderr data to the client. */
 549         if (buffer_len(&stderr_buffer) > 0) {
 550                 packet_start(SSH_SMSG_STDERR_DATA);
 551                 packet_put_string(buffer_ptr(&stderr_buffer),
 552                                   buffer_len(&stderr_buffer));
 553                 packet_send();
 554                 /* Update the count of sent bytes. */
 555                 stderr_bytes += buffer_len(&stderr_buffer);
 556         }
 557         /* Wait until all buffered data has been written to the client. */
 558         packet_write_wait();
 559 }
 560
 561 static void
 562 process_buffered_input_packets(void)
 563 {
 564         dispatch_run(DISPATCH_NONBLOCK, NULL, compat20 ? xxx_kex : NULL);
 565 }
 566
 567 /*
 568  * Performs the interactive session.  This handles data transmission between
 569  * the client and the program.  Note that the notion of stdin, stdout, and
 570  * stderr in this function is sort of reversed: this function writes to
 571  * stdin (of the child program), and reads from stdout and stderr (of the
 572  * child program).
 573  */
 574 void
 575 server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
 576 {
 577         fd_set *readset = NULL, *writeset = NULL;
 578         int max_fd = 0;
 579         u_int nalloc = 0;
 580         int wait_status;        /* Status returned by wait(). */
 581         pid_t wait_pid;         /* pid returned by wait(). */
 582         int waiting_termination = 0;    /* Have displayed waiting close message. */
 583         u_int64_t max_time_milliseconds;
 584         u_int previous_stdout_buffer_bytes;
 585         u_int stdout_buffer_bytes;
 586         int type;
 587
 588         debug("Entering interactive session.");
 589
 590         /* Initialize the SIGCHLD kludge. */
 591         child_terminated = 0;
 592         mysignal(SIGCHLD, sigchld_handler);
 593
 594         if (!use_privsep) {
 595                 signal(SIGTERM, sigterm_handler);
 596                 signal(SIGINT, sigterm_handler);
 597                 signal(SIGQUIT, sigterm_handler);
 598         }
 599
 600         /* Initialize our global variables. */
 601         fdin = fdin_arg;
 602         fdout = fdout_arg;
 603         fderr = fderr_arg;
 604
 605         /* nonblocking IO */
 606         set_nonblock(fdin);
 607         set_nonblock(fdout);
 608         /* we don't have stderr for interactive terminal sessions, see below */
 609         if (fderr != -1)
 610                 set_nonblock(fderr);
 611
 612         if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin))
 613                 fdin_is_tty = 1;
 614
 615         connection_in = packet_get_connection_in();
 616         connection_out = packet_get_connection_out();
 617
 618         notify_setup();
 619
 620         previous_stdout_buffer_bytes = 0;
 621
 622         /* Set approximate I/O buffer size. */
 623         if (packet_is_interactive())
 624                 buffer_high = 4096;
 625         else
 626                 buffer_high = 64 * 1024;
 627
 628 #if 0
 629         /* Initialize max_fd to the maximum of the known file descriptors. */
 630         max_fd = MAX(connection_in, connection_out);
 631         max_fd = MAX(max_fd, fdin);
 632         max_fd = MAX(max_fd, fdout);
 633         if (fderr != -1)
 634                 max_fd = MAX(max_fd, fderr);
 635 #endif
 636
 637         /* Initialize Initialize buffers. */
 638         buffer_init(&stdin_buffer);
 639         buffer_init(&stdout_buffer);
 640         buffer_init(&stderr_buffer);
 641
 642         /*
 643          * If we have no separate fderr (which is the case when we have a pty
 644          * - there we cannot make difference between data sent to stdout and
 645          * stderr), indicate that we have seen an EOF from stderr.  This way
 646          * we don't need to check the descriptor everywhere.
 647          */
 648         if (fderr == -1)
 649                 fderr_eof = 1;
 650
 651         server_init_dispatch();
 652
 653         /* Main loop of the server for the interactive session mode. */
 654         for (;;) {
 655
 656                 /* Process buffered packets from the client. */
 657                 process_buffered_input_packets();
 658
 659                 /*
 660                  * If we have received eof, and there is no more pending
 661                  * input data, cause a real eof by closing fdin.
 662                  */
 663                 if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) {
 664                         if (fdin != fdout)
 665                                 close(fdin);
 666                         else
 667                                 shutdown(fdin, SHUT_WR); /* We will no longer send. */
 668                         fdin = -1;
 669                 }
 670                 /* Make packets from buffered stderr data to send to the client. */
 671                 make_packets_from_stderr_data();
 672
 673                 /*
 674                  * Make packets from buffered stdout data to send to the
 675                  * client. If there is very little to send, this arranges to
 676                  * not send them now, but to wait a short while to see if we
 677                  * are getting more data. This is necessary, as some systems
 678                  * wake up readers from a pty after each separate character.
 679                  */
 680                 max_time_milliseconds = 0;
 681                 stdout_buffer_bytes = buffer_len(&stdout_buffer);
 682                 if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 &&
 683                     stdout_buffer_bytes != previous_stdout_buffer_bytes) {
 684                         /* try again after a while */
 685                         max_time_milliseconds = 10;
 686                 } else {
 687                         /* Send it now. */
 688                         make_packets_from_stdout_data();
 689                 }
 690                 previous_stdout_buffer_bytes = buffer_len(&stdout_buffer);
 691
 692                 /* Send channel data to the client. */
 693                 if (packet_not_very_much_data_to_write())
 694                         channel_output_poll();
 695
 696                 /*
 697                  * Bail out of the loop if the program has closed its output
 698                  * descriptors, and we have no more data to send to the
 699                  * client, and there is no pending buffered data.
 700                  */
 701                 if (fdout_eof && fderr_eof && !packet_have_data_to_write() &&
 702                     buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) {
 703                         if (!channel_still_open())
 704                                 break;
 705                         if (!waiting_termination) {
 706                                 const char *s = "Waiting for forwarded connections to terminate...\r\n";
 707                                 char *cp;
 708                                 waiting_termination = 1;
 709                                 buffer_append(&stderr_buffer, s, strlen(s));
 710
 711                                 /* Display list of open channels. */
 712                                 cp = channel_open_message();
 713                                 buffer_append(&stderr_buffer, cp, strlen(cp));
 714                                 free(cp);
 715                         }
 716                 }
 717                 max_fd = MAX(connection_in, connection_out);
 718                 max_fd = MAX(max_fd, fdin);
 719                 max_fd = MAX(max_fd, fdout);
 720                 max_fd = MAX(max_fd, fderr);
 721                 max_fd = MAX(max_fd, notify_pipe[0]);
 722
 723                 /* Sleep in select() until we can do something. */
 724                 wait_until_can_do_something(&readset, &writeset, &max_fd,
 725                     &nalloc, max_time_milliseconds);
 726
 727                 if (received_sigterm) {
 728                         logit("Exiting on signal %d", (int)received_sigterm);
 729                         /* Clean up sessions, utmp, etc. */
 730                         cleanup_exit(255);
 731                 }
 732
 733                 /* Process any channel events. */
 734                 channel_after_select(readset, writeset);
 735
 736                 /* Process input from the client and from program stdout/stderr. */
 737                 process_input(readset);
 738
 739                 /* Process output to the client and to program stdin. */
 740                 process_output(writeset);
 741         }
 742         free(readset);
 743         free(writeset);
 744
 745         /* Cleanup and termination code. */
 746
 747         /* Wait until all output has been sent to the client. */
 748         drain_output();
 749
 750         debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.",
 751             stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes);
 752
 753         /* Free and clear the buffers. */
 754         buffer_free(&stdin_buffer);
 755         buffer_free(&stdout_buffer);
 756         buffer_free(&stderr_buffer);
 757
 758         /* Close the file descriptors. */
 759         if (fdout != -1)
 760                 close(fdout);
 761         fdout = -1;
 762         fdout_eof = 1;
 763         if (fderr != -1)
 764                 close(fderr);
 765         fderr = -1;
 766         fderr_eof = 1;
 767         if (fdin != -1)
 768                 close(fdin);
 769         fdin = -1;
 770
 771         channel_free_all();
 772
 773         /* We no longer want our SIGCHLD handler to be called. */
 774         mysignal(SIGCHLD, SIG_DFL);
 775
 776         while ((wait_pid = waitpid(-1, &wait_status, 0)) < 0)
 777                 if (errno != EINTR)
 778                         packet_disconnect("wait: %.100s", strerror(errno));
 779         if (wait_pid != pid)
 780                 error("Strange, wait returned pid %ld, expected %ld",
 781                     (long)wait_pid, (long)pid);
 782
 783         /* Check if it exited normally. */
 784         if (WIFEXITED(wait_status)) {
 785                 /* Yes, normal exit.  Get exit status and send it to the client. */
 786                 debug("Command exited with status %d.", WEXITSTATUS(wait_status));
 787                 packet_start(SSH_SMSG_EXITSTATUS);
 788                 packet_put_int(WEXITSTATUS(wait_status));
 789                 packet_send();
 790                 packet_write_wait();
 791
 792                 /*
 793                  * Wait for exit confirmation.  Note that there might be
 794                  * other packets coming before it; however, the program has
 795                  * already died so we just ignore them.  The client is
 796                  * supposed to respond with the confirmation when it receives
 797                  * the exit status.
 798                  */
 799                 do {
 800                         type = packet_read();
 801                 }
 802                 while (type != SSH_CMSG_EXIT_CONFIRMATION);
 803
 804                 debug("Received exit confirmation.");
 805                 return;
 806         }
 807         /* Check if the program terminated due to a signal. */
 808         if (WIFSIGNALED(wait_status))
 809                 packet_disconnect("Command terminated on signal %d.",
 810                                   WTERMSIG(wait_status));
 811
 812         /* Some weird exit cause.  Just exit. */
 813         packet_disconnect("wait returned status %04x.", wait_status);
 814         /* NOTREACHED */
 815 }
 816
 817 static void
 818 collect_children(void)
 819 {
 820         pid_t pid;
 821         sigset_t oset, nset;
 822         int status;
 823
 824         /* block SIGCHLD while we check for dead children */
 825         sigemptyset(&nset);
 826         sigaddset(&nset, SIGCHLD);
 827         sigprocmask(SIG_BLOCK, &nset, &oset);
 828         if (child_terminated) {
 829                 debug("Received SIGCHLD.");
 830                 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
 831                     (pid < 0 && errno == EINTR))
 832                         if (pid > 0)
 833                                 session_close_by_pid(pid, status);
 834                 child_terminated = 0;
 835         }
 836         sigprocmask(SIG_SETMASK, &oset, NULL);
 837 }
 838
 839 void
 840 server_loop2(Authctxt *authctxt)
 841 {
 842         fd_set *readset = NULL, *writeset = NULL;
 843         int rekeying = 0, max_fd;
 844         double start_time, total_time;
 845         u_int nalloc = 0;
 846         u_int64_t rekey_timeout_ms = 0;
 847
 848         debug("Entering interactive session for SSH2.");
 849         start_time = get_current_time();
 850
 851         mysignal(SIGCHLD, sigchld_handler);
 852         child_terminated = 0;
 853         connection_in = packet_get_connection_in();
 854         connection_out = packet_get_connection_out();
 855
 856         if (!use_privsep) {
 857                 signal(SIGTERM, sigterm_handler);
 858                 signal(SIGINT, sigterm_handler);
 859                 signal(SIGQUIT, sigterm_handler);
 860         }
 861
 862         notify_setup();
 863
 864         max_fd = MAX(connection_in, connection_out);
 865         max_fd = MAX(max_fd, notify_pipe[0]);
 866
 867         server_init_dispatch();
 868
 869         for (;;) {
 870                 process_buffered_input_packets();
 871
 872                 rekeying = (xxx_kex != NULL && !xxx_kex->done);
 873
 874                 if (!rekeying && packet_not_very_much_data_to_write())
 875                         channel_output_poll();
 876                 if (options.rekey_interval > 0 && compat20 && !rekeying)
 877                         rekey_timeout_ms = packet_get_rekey_timeout() * 1000;
 878                 else
 879                         rekey_timeout_ms = 0;
 880
 881                 wait_until_can_do_something(&readset, &writeset, &max_fd,
 882                     &nalloc, rekey_timeout_ms);
 883
 884                 if (received_sigterm) {
 885                         logit("Exiting on signal %d", (int)received_sigterm);
 886                         /* Clean up sessions, utmp, etc. */
 887                         cleanup_exit(255);
 888                 }
 889
 890                 collect_children();
 891                 if (!rekeying) {
 892                         channel_after_select(readset, writeset);
 893                         if (packet_need_rekeying()) {
 894                                 debug("need rekeying");
 895                                 xxx_kex->done = 0;
 896                                 kex_send_kexinit(xxx_kex);
 897                         }
 898                 }
 899                 process_input(readset);
 900                 if (connection_closed)
 901                         break;
 902                 process_output(writeset);
 903         }
 904         collect_children();
 905
 906         free(readset);
 907         free(writeset);
 908
 909         /* free all channels, no more reads and writes */
 910         channel_free_all();
 911
 912         /* free remaining sessions, e.g. remove wtmp entries */
 913         session_destroy_all(NULL);
 914         total_time = get_current_time() - start_time;
 915         logit("SSH: Server;LType: Throughput;Remote: %s-%d;IN: %lu;OUT: %lu;Duration: %.1f;tPut_in: %.1f;tPut_out: %.1f",
 916               get_remote_ipaddr(), get_remote_port(),
 917               stdin_bytes, fdout_bytes, total_time, stdin_bytes / total_time,
 918               fdout_bytes / total_time);
 919 }
 920
 921 static void
 922 server_input_keep_alive(int type, u_int32_t seq, void *ctxt)
 923 {
 924         debug("Got %d/%u for keepalive", type, seq);
 925         /*
 926          * reset timeout, since we got a sane answer from the client.
 927          * even if this was generated by something other than
 928          * the bogus CHANNEL_REQUEST we send for keepalives.
 929          */
 930         packet_set_alive_timeouts(0);
 931 }
 932
 933 static void
 934 server_input_stdin_data(int type, u_int32_t seq, void *ctxt)
 935 {
 936         char *data;
 937         u_int data_len;
 938
 939         /* Stdin data from the client.  Append it to the buffer. */
 940         /* Ignore any data if the client has closed stdin. */
 941         if (fdin == -1)
 942                 return;
 943         data = packet_get_string(&data_len);
 944         packet_check_eom();
 945         buffer_append(&stdin_buffer, data, data_len);
 946         explicit_bzero(data, data_len);
 947         free(data);
 948 }
 949
 950 static void
 951 server_input_eof(int type, u_int32_t seq, void *ctxt)
 952 {
 953         /*
 954          * Eof from the client.  The stdin descriptor to the
 955          * program will be closed when all buffered data has
 956          * drained.
 957          */
 958         debug("EOF received for stdin.");
 959         packet_check_eom();
 960         stdin_eof = 1;
 961 }
 962
 963 static void
 964 server_input_window_size(int type, u_int32_t seq, void *ctxt)
 965 {
 966         u_int row = packet_get_int();
 967         u_int col = packet_get_int();
 968         u_int xpixel = packet_get_int();
 969         u_int ypixel = packet_get_int();
 970
 971         debug("Window change received.");
 972         packet_check_eom();
 973         if (fdin != -1)
 974                 pty_change_window_size(fdin, row, col, xpixel, ypixel);
 975 }
 976
 977 static Channel *
 978 server_request_direct_tcpip(void)
 979 {
 980         Channel *c = NULL;
 981         char *target, *originator;
 982         u_short target_port, originator_port;
 983
 984         target = packet_get_string(NULL);
 985         target_port = packet_get_int();
 986         originator = packet_get_string(NULL);
 987         originator_port = packet_get_int();
 988         packet_check_eom();
 989
 990         debug("server_request_direct_tcpip: originator %s port %d, target %s "
 991             "port %d", originator, originator_port, target, target_port);
 992
 993         /* XXX fine grained permissions */
 994         if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0 &&
 995             !no_port_forwarding_flag) {
 996                 c = channel_connect_to_port(target, target_port,
 997                     "direct-tcpip", "direct-tcpip");
 998         } else {
 999                 logit("refused local port forward: "
1000                     "originator %s port %d, target %s port %d",
1001                     originator, originator_port, target, target_port);
1002         }
1003
1004         free(originator);
1005         free(target);
1006
1007         return c;
1008 }
1009
1010 static Channel *
1011 server_request_direct_streamlocal(void)
1012 {
1013         Channel *c = NULL;
1014         char *target, *originator;
1015         u_short originator_port;
1016
1017         target = packet_get_string(NULL);
1018         originator = packet_get_string(NULL);
1019         originator_port = packet_get_int();
1020         packet_check_eom();
1021
1022         debug("server_request_direct_streamlocal: originator %s port %d, target %s",
1023             originator, originator_port, target);
1024
1025         /* XXX fine grained permissions */
1026         if ((options.allow_streamlocal_forwarding & FORWARD_LOCAL) != 0 &&
1027             !no_port_forwarding_flag) {
1028                 c = channel_connect_to_path(target,
1029                     "direct-streamlocal@openssh.com", "direct-streamlocal");
1030         } else {
1031                 logit("refused streamlocal port forward: "
1032                     "originator %s port %d, target %s",
1033                     originator, originator_port, target);
1034         }
1035
1036         free(originator);
1037         free(target);
1038
1039         return c;
1040 }
1041
1042 static Channel *
1043 server_request_tun(void)
1044 {
1045         Channel *c = NULL;
1046         int mode, tun;
1047         int sock;
1048
1049         mode = packet_get_int();
1050         switch (mode) {
1051         case SSH_TUNMODE_POINTOPOINT:
1052         case SSH_TUNMODE_ETHERNET:
1053                 break;
1054         default:
1055                 packet_send_debug("Unsupported tunnel device mode.");
1056                 return NULL;
1057         }
1058         if ((options.permit_tun & mode) == 0) {
1059                 packet_send_debug("Server has rejected tunnel device "
1060                     "forwarding");
1061                 return NULL;
1062         }
1063
1064         tun = packet_get_int();
1065         if (forced_tun_device != -1) {
1066                 if (tun != SSH_TUNID_ANY && forced_tun_device != tun)
1067                         goto done;
1068                 tun = forced_tun_device;
1069         }
1070         sock = tun_open(tun, mode);
1071         if (sock < 0)
1072                 goto done;
1073         if (options.hpn_disabled)
1074         c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1075             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1076         else
1077                 c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1078                     options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1079         c->datagram = 1;
1080 #if defined(SSH_TUN_FILTER)
1081         if (mode == SSH_TUNMODE_POINTOPOINT)
1082                 channel_register_filter(c->self, sys_tun_infilter,
1083                     sys_tun_outfilter, NULL, NULL);
1084 #endif
1085
1086  done:
1087         if (c == NULL)
1088                 packet_send_debug("Failed to open the tunnel device.");
1089         return c;
1090 }
1091
1092 static Channel *
1093 server_request_session(void)
1094 {
1095         Channel *c;
1096
1097         debug("input_session_request");
1098         packet_check_eom();
1099
1100         if (no_more_sessions) {
1101                 packet_disconnect("Possible attack: attempt to open a session "
1102                     "after additional sessions disabled");
1103         }
1104
1105         /*
1106          * A server session has no fd to read or write until a
1107          * CHANNEL_REQUEST for a shell is made, so we set the type to
1108          * SSH_CHANNEL_LARVAL.  Additionally, a callback for handling all
1109          * CHANNEL_REQUEST messages is registered.
1110          */
1111         c = channel_new("session", SSH_CHANNEL_LARVAL,
1112             -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
1113             0, "server-session", 1);
1114         if ((options.tcp_rcv_buf_poll) && (!options.hpn_disabled))
1115                 c->dynamic_window = 1;
1116         if (session_open(the_authctxt, c->self) != 1) {
1117                 debug("session open failed, free channel %d", c->self);
1118                 channel_free(c);
1119                 return NULL;
1120         }
1121         channel_register_cleanup(c->self, session_close_by_channel, 0);
1122         return c;
1123 }
1124
1125 static void
1126 server_input_channel_open(int type, u_int32_t seq, void *ctxt)
1127 {
1128         Channel *c = NULL;
1129         char *ctype;
1130         int rchan;
1131         u_int rmaxpack, rwindow, len;
1132
1133         ctype = packet_get_string(&len);
1134         rchan = packet_get_int();
1135         rwindow = packet_get_int();
1136         rmaxpack = packet_get_int();
1137
1138         debug("server_input_channel_open: ctype %s rchan %d win %d max %d",
1139             ctype, rchan, rwindow, rmaxpack);
1140
1141         if (strcmp(ctype, "session") == 0) {
1142                 c = server_request_session();
1143         } else if (strcmp(ctype, "direct-tcpip") == 0) {
1144                 c = server_request_direct_tcpip();
1145         } else if (strcmp(ctype, "direct-streamlocal@openssh.com") == 0) {
1146                 c = server_request_direct_streamlocal();
1147         } else if (strcmp(ctype, "tun@openssh.com") == 0) {
1148                 c = server_request_tun();
1149         }
1150         if (c != NULL) {
1151                 debug("server_input_channel_open: confirm %s", ctype);
1152                 c->remote_id = rchan;
1153                 c->remote_window = rwindow;
1154                 c->remote_maxpacket = rmaxpack;
1155                 if (c->type != SSH_CHANNEL_CONNECTING) {
1156                         packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1157                         packet_put_int(c->remote_id);
1158                         packet_put_int(c->self);
1159                         packet_put_int(c->local_window);
1160                         packet_put_int(c->local_maxpacket);
1161                         packet_send();
1162                 }
1163         } else {
1164                 debug("server_input_channel_open: failure %s", ctype);
1165                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1166                 packet_put_int(rchan);
1167                 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1168                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1169                         packet_put_cstring("open failed");
1170                         packet_put_cstring("");
1171                 }
1172                 packet_send();
1173         }
1174         free(ctype);
1175 }
1176
1177 static void
1178 server_input_global_request(int type, u_int32_t seq, void *ctxt)
1179 {
1180         char *rtype;
1181         int want_reply;
1182         int success = 0, allocated_listen_port = 0;
1183
1184         rtype = packet_get_string(NULL);
1185         want_reply = packet_get_char();
1186         debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
1187
1188         /* -R style forwarding */
1189         if (strcmp(rtype, "tcpip-forward") == 0) {
1190                 struct passwd *pw;
1191                 struct Forward fwd;
1192
1193                 pw = the_authctxt->pw;
1194                 if (pw == NULL || !the_authctxt->valid)
1195                         fatal("server_input_global_request: no/invalid user");
1196                 memset(&fwd, 0, sizeof(fwd));
1197                 fwd.listen_host = packet_get_string(NULL);
1198                 fwd.listen_port = (u_short)packet_get_int();
1199                 debug("server_input_global_request: tcpip-forward listen %s port %d",
1200                     fwd.listen_host, fwd.listen_port);
1201
1202                 /* check permissions */
1203                 if ((options.allow_tcp_forwarding & FORWARD_REMOTE) == 0 ||
1204                     no_port_forwarding_flag ||
1205                     (!want_reply && fwd.listen_port == 0)
1206 #ifndef NO_IPPORT_RESERVED_CONCEPT
1207                     || (fwd.listen_port != 0 && fwd.listen_port < IPPORT_RESERVED &&
1208                     pw->pw_uid != 0)
1209 #endif
1210                     ) {
1211                         success = 0;
1212                         packet_send_debug("Server has disabled port forwarding.");
1213                 } else {
1214                         /* Start listening on the port */
1215                         success = channel_setup_remote_fwd_listener(&fwd,
1216                             &allocated_listen_port, &options.fwd_opts);
1217                 }
1218                 free(fwd.listen_host);
1219         } else if (strcmp(rtype, "cancel-tcpip-forward") == 0) {
1220                 struct Forward fwd;
1221
1222                 memset(&fwd, 0, sizeof(fwd));
1223                 fwd.listen_host = packet_get_string(NULL);
1224                 fwd.listen_port = (u_short)packet_get_int();
1225                 debug("%s: cancel-tcpip-forward addr %s port %d", __func__,
1226                     fwd.listen_host, fwd.listen_port);
1227
1228                 success = channel_cancel_rport_listener(&fwd);
1229                 free(fwd.listen_host);
1230         } else if (strcmp(rtype, "streamlocal-forward@openssh.com") == 0) {
1231                 struct Forward fwd;
1232
1233                 memset(&fwd, 0, sizeof(fwd));
1234                 fwd.listen_path = packet_get_string(NULL);
1235                 debug("server_input_global_request: streamlocal-forward listen path %s",
1236                     fwd.listen_path);
1237
1238                 /* check permissions */
1239                 if ((options.allow_streamlocal_forwarding & FORWARD_REMOTE) == 0
1240                     || no_port_forwarding_flag) {
1241                         success = 0;
1242                         packet_send_debug("Server has disabled port forwarding.");
1243                 } else {
1244                         /* Start listening on the socket */
1245                         success = channel_setup_remote_fwd_listener(
1246                             &fwd, NULL, &options.fwd_opts);
1247                 }
1248                 free(fwd.listen_path);
1249         } else if (strcmp(rtype, "cancel-streamlocal-forward@openssh.com") == 0) {
1250                 struct Forward fwd;
1251
1252                 memset(&fwd, 0, sizeof(fwd));
1253                 fwd.listen_path = packet_get_string(NULL);
1254                 debug("%s: cancel-streamlocal-forward path %s", __func__,
1255                     fwd.listen_path);
1256
1257                 success = channel_cancel_rport_listener(&fwd);
1258                 free(fwd.listen_path);
1259         } else if (strcmp(rtype, "no-more-sessions@openssh.com") == 0) {
1260                 no_more_sessions = 1;
1261                 success = 1;
1262         }
1263         if (want_reply) {
1264                 packet_start(success ?
1265                     SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1266                 if (success && allocated_listen_port > 0)
1267                         packet_put_int(allocated_listen_port);
1268                 packet_send();
1269                 packet_write_wait();
1270         }
1271         free(rtype);
1272 }
1273
1274 static void
1275 server_input_channel_req(int type, u_int32_t seq, void *ctxt)
1276 {
1277         Channel *c;
1278         int id, reply, success = 0;
1279         char *rtype;
1280
1281         id = packet_get_int();
1282         rtype = packet_get_string(NULL);
1283         reply = packet_get_char();
1284
1285         debug("server_input_channel_req: channel %d request %s reply %d",
1286             id, rtype, reply);
1287
1288         if ((c = channel_lookup(id)) == NULL)
1289                 packet_disconnect("server_input_channel_req: "
1290                     "unknown channel %d", id);
1291         if (!strcmp(rtype, "eow@openssh.com")) {
1292                 packet_check_eom();
1293                 chan_rcvd_eow(c);
1294         } else if ((c->type == SSH_CHANNEL_LARVAL ||
1295             c->type == SSH_CHANNEL_OPEN) && strcmp(c->ctype, "session") == 0)
1296                 success = session_input_channel_req(c, rtype);
1297         if (reply && !(c->flags & CHAN_CLOSE_SENT)) {
1298                 packet_start(success ?
1299                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1300                 packet_put_int(c->remote_id);
1301                 packet_send();
1302         }
1303         free(rtype);
1304 }
1305
1306 static void
1307 server_init_dispatch_20(void)
1308 {
1309         debug("server_init_dispatch_20");
1310         dispatch_init(&dispatch_protocol_error);
1311         dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1312         dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1313         dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1314         dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1315         dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open);
1316         dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1317         dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1318         dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &server_input_channel_req);
1319         dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1320         dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
1321         /* client_alive */
1322         dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &server_input_keep_alive);
1323         dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_keep_alive);
1324         dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &server_input_keep_alive);
1325         dispatch_set(SSH2_MSG_REQUEST_FAILURE, &server_input_keep_alive);
1326         /* rekeying */
1327         dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1328 }
1329 static void
1330 server_init_dispatch_13(void)
1331 {
1332         debug("server_init_dispatch_13");
1333         dispatch_init(NULL);
1334         dispatch_set(SSH_CMSG_EOF, &server_input_eof);
1335         dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data);
1336         dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size);
1337         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1338         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1339         dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1340         dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1341         dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1342         dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1343 }
1344 static void
1345 server_init_dispatch_15(void)
1346 {
1347         server_init_dispatch_13();
1348         debug("server_init_dispatch_15");
1349         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1350         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose);
1351 }
1352 static void
1353 server_init_dispatch(void)
1354 {
1355         if (compat20)
1356                 server_init_dispatch_20();
1357         else if (compat13)
1358                 server_init_dispatch_13();
1359         else
1360                 server_init_dispatch_15();
1361 }