clientloop.c

   1 /*
   2  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   3  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   4  *                    All rights reserved
   5  * The main loop for the interactive session (client side).
   6  *
   7  * As far as I am concerned, the code I have written for this software
   8  * can be used freely for any purpose.  Any derived versions of this
   9  * software must be clearly marked as such, and if the derived work is
  10  * incompatible with the protocol description in the RFC file, it must be
  11  * called by a name other than "ssh" or "Secure Shell".
  12  *
  13  *
  14  * Copyright (c) 1999 Theo de Raadt.  All rights reserved.
  15  *
  16  * Redistribution and use in source and binary forms, with or without
  17  * modification, are permitted provided that the following conditions
  18  * are met:
  19  * 1. Redistributions of source code must retain the above copyright
  20  *    notice, this list of conditions and the following disclaimer.
  21  * 2. Redistributions in binary form must reproduce the above copyright
  22  *    notice, this list of conditions and the following disclaimer in the
  23  *    documentation and/or other materials provided with the distribution.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  26  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  27  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  28  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  29  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  30  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  31  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  32  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  34  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  35  *
  36  *
  37  * SSH2 support added by Markus Friedl.
  38  * Copyright (c) 1999, 2000, 2001 Markus Friedl.  All rights reserved.
  39  *
  40  * Redistribution and use in source and binary forms, with or without
  41  * modification, are permitted provided that the following conditions
  42  * are met:
  43  * 1. Redistributions of source code must retain the above copyright
  44  *    notice, this list of conditions and the following disclaimer.
  45  * 2. Redistributions in binary form must reproduce the above copyright
  46  *    notice, this list of conditions and the following disclaimer in the
  47  *    documentation and/or other materials provided with the distribution.
  48  *
  49  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  50  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  51  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  52  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  53  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  54  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  55  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  56  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  57  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  58  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  59  */
  60
  61 #include "includes.h"
  62 RCSID("$OpenBSD: clientloop.c,v 1.137 2005/06/08 11:25:09 djm Exp $");
  63
  64 #include "ssh.h"
  65 #include "ssh1.h"
  66 #include "ssh2.h"
  67 #include "xmalloc.h"
  68 #include "packet.h"
  69 #include "buffer.h"
  70 #include "compat.h"
  71 #include "channels.h"
  72 #include "dispatch.h"
  73 #include "buffer.h"
  74 #include "bufaux.h"
  75 #include "key.h"
  76 #include "kex.h"
  77 #include "log.h"
  78 #include "readconf.h"
  79 #include "clientloop.h"
  80 #include "authfd.h"
  81 #include "atomicio.h"
  82 #include "sshpty.h"
  83 #include "misc.h"
  84 #include "monitor_fdpass.h"
  85 #include "match.h"
  86 #include "msg.h"
  87
  88 /* import options */
  89 extern Options options;
  90
  91 /* Flag indicating that stdin should be redirected from /dev/null. */
  92 extern int stdin_null_flag;
  93
  94 /* Flag indicating that no shell has been requested */
  95 extern int no_shell_flag;
  96
  97 /* Control socket */
  98 extern int control_fd;
  99
 100 /*
 101  * Name of the host we are connecting to.  This is the name given on the
 102  * command line, or the HostName specified for the user-supplied name in a
 103  * configuration file.
 104  */
 105 extern char *host;
 106
 107 /*
 108  * Flag to indicate that we have received a window change signal which has
 109  * not yet been processed.  This will cause a message indicating the new
 110  * window size to be sent to the server a little later.  This is volatile
 111  * because this is updated in a signal handler.
 112  */
 113 static volatile sig_atomic_t received_window_change_signal = 0;
 114 static volatile sig_atomic_t received_signal = 0;
 115
 116 /* Flag indicating whether the user\'s terminal is in non-blocking mode. */
 117 static int in_non_blocking_mode = 0;
 118
 119 /* Common data for the client loop code. */
 120 static int quit_pending;        /* Set to non-zero to quit the client loop. */
 121 static int escape_char;         /* Escape character. */
 122 static int escape_pending;      /* Last character was the escape character */
 123 static int last_was_cr;         /* Last character was a newline. */
 124 static int exit_status;         /* Used to store the exit status of the command. */
 125 static int stdin_eof;           /* EOF has been encountered on standard error. */
 126 static Buffer stdin_buffer;     /* Buffer for stdin data. */
 127 static Buffer stdout_buffer;    /* Buffer for stdout data. */
 128 static Buffer stderr_buffer;    /* Buffer for stderr data. */
 129 static u_long stdin_bytes, stdout_bytes, stderr_bytes;
 130 static u_int buffer_high;/* Soft max buffer size. */
 131 static int connection_in;       /* Connection to server (input). */
 132 static int connection_out;      /* Connection to server (output). */
 133 static int need_rekeying;       /* Set to non-zero if rekeying is requested. */
 134 static int session_closed = 0;  /* In SSH2: login session closed. */
 135 static int server_alive_timeouts = 0;
 136
 137 static void client_init_dispatch(void);
 138 int     session_ident = -1;
 139
 140 struct confirm_ctx {
 141         int want_tty;
 142         int want_subsys;
 143         Buffer cmd;
 144         char *term;
 145         struct termios tio;
 146         char **env;
 147 };
 148
 149 /*XXX*/
 150 extern Kex *xxx_kex;
 151
 152 void ssh_process_session2_setup(int, int, int, Buffer *);
 153
 154 /* Restores stdin to blocking mode. */
 155
 156 static void
 157 leave_non_blocking(void)
 158 {
 159         if (in_non_blocking_mode) {
 160                 unset_nonblock(fileno(stdin));
 161                 in_non_blocking_mode = 0;
 162         }
 163 }
 164
 165 /* Puts stdin terminal in non-blocking mode. */
 166
 167 static void
 168 enter_non_blocking(void)
 169 {
 170         in_non_blocking_mode = 1;
 171         set_nonblock(fileno(stdin));
 172 }
 173
 174 /*
 175  * Signal handler for the window change signal (SIGWINCH).  This just sets a
 176  * flag indicating that the window has changed.
 177  */
 178
 179 static void
 180 window_change_handler(int sig)
 181 {
 182         received_window_change_signal = 1;
 183         signal(SIGWINCH, window_change_handler);
 184 }
 185
 186 /*
 187  * Signal handler for signals that cause the program to terminate.  These
 188  * signals must be trapped to restore terminal modes.
 189  */
 190
 191 static void
 192 signal_handler(int sig)
 193 {
 194         received_signal = sig;
 195         quit_pending = 1;
 196 }
 197
 198 /*
 199  * Returns current time in seconds from Jan 1, 1970 with the maximum
 200  * available resolution.
 201  */
 202
 203 static double
 204 get_current_time(void)
 205 {
 206         struct timeval tv;
 207         gettimeofday(&tv, NULL);
 208         return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
 209 }
 210
 211 /*
 212  * This is called when the interactive is entered.  This checks if there is
 213  * an EOF coming on stdin.  We must check this explicitly, as select() does
 214  * not appear to wake up when redirecting from /dev/null.
 215  */
 216
 217 static void
 218 client_check_initial_eof_on_stdin(void)
 219 {
 220         int len;
 221         char buf[1];
 222
 223         /*
 224          * If standard input is to be "redirected from /dev/null", we simply
 225          * mark that we have seen an EOF and send an EOF message to the
 226          * server. Otherwise, we try to read a single character; it appears
 227          * that for some files, such /dev/null, select() never wakes up for
 228          * read for this descriptor, which means that we never get EOF.  This
 229          * way we will get the EOF if stdin comes from /dev/null or similar.
 230          */
 231         if (stdin_null_flag) {
 232                 /* Fake EOF on stdin. */
 233                 debug("Sending eof.");
 234                 stdin_eof = 1;
 235                 packet_start(SSH_CMSG_EOF);
 236                 packet_send();
 237         } else {
 238                 enter_non_blocking();
 239
 240                 /* Check for immediate EOF on stdin. */
 241                 len = read(fileno(stdin), buf, 1);
 242                 if (len == 0) {
 243                         /* EOF.  Record that we have seen it and send EOF to server. */
 244                         debug("Sending eof.");
 245                         stdin_eof = 1;
 246                         packet_start(SSH_CMSG_EOF);
 247                         packet_send();
 248                 } else if (len > 0) {
 249                         /*
 250                          * Got data.  We must store the data in the buffer,
 251                          * and also process it as an escape character if
 252                          * appropriate.
 253                          */
 254                         if ((u_char) buf[0] == escape_char)
 255                                 escape_pending = 1;
 256                         else
 257                                 buffer_append(&stdin_buffer, buf, 1);
 258                 }
 259                 leave_non_blocking();
 260         }
 261 }
 262
 263
 264 /*
 265  * Make packets from buffered stdin data, and buffer them for sending to the
 266  * connection.
 267  */
 268
 269 static void
 270 client_make_packets_from_stdin_data(void)
 271 {
 272         u_int len;
 273
 274         /* Send buffered stdin data to the server. */
 275         while (buffer_len(&stdin_buffer) > 0 &&
 276             packet_not_very_much_data_to_write()) {
 277                 len = buffer_len(&stdin_buffer);
 278                 /* Keep the packets at reasonable size. */
 279                 if (len > packet_get_maxsize())
 280                         len = packet_get_maxsize();
 281                 packet_start(SSH_CMSG_STDIN_DATA);
 282                 packet_put_string(buffer_ptr(&stdin_buffer), len);
 283                 packet_send();
 284                 buffer_consume(&stdin_buffer, len);
 285                 stdin_bytes += len;
 286                 /* If we have a pending EOF, send it now. */
 287                 if (stdin_eof && buffer_len(&stdin_buffer) == 0) {
 288                         packet_start(SSH_CMSG_EOF);
 289                         packet_send();
 290                 }
 291         }
 292 }
 293
 294 /*
 295  * Checks if the client window has changed, and sends a packet about it to
 296  * the server if so.  The actual change is detected elsewhere (by a software
 297  * interrupt on Unix); this just checks the flag and sends a message if
 298  * appropriate.
 299  */
 300
 301 static void
 302 client_check_window_change(void)
 303 {
 304         struct winsize ws;
 305
 306         if (! received_window_change_signal)
 307                 return;
 308         /** XXX race */
 309         received_window_change_signal = 0;
 310
 311         debug2("client_check_window_change: changed");
 312
 313         if (compat20) {
 314                 channel_send_window_changes();
 315         } else {
 316                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
 317                         return;
 318                 packet_start(SSH_CMSG_WINDOW_SIZE);
 319                 packet_put_int(ws.ws_row);
 320                 packet_put_int(ws.ws_col);
 321                 packet_put_int(ws.ws_xpixel);
 322                 packet_put_int(ws.ws_ypixel);
 323                 packet_send();
 324         }
 325 }
 326
 327 static void
 328 client_global_request_reply(int type, u_int32_t seq, void *ctxt)
 329 {
 330         server_alive_timeouts = 0;
 331         client_global_request_reply_fwd(type, seq, ctxt);
 332 }
 333
 334 static void
 335 server_alive_check(void)
 336 {
 337         if (++server_alive_timeouts > options.server_alive_count_max)
 338                 packet_disconnect("Timeout, server not responding.");
 339         packet_start(SSH2_MSG_GLOBAL_REQUEST);
 340         packet_put_cstring("keepalive@openssh.com");
 341         packet_put_char(1);     /* boolean: want reply */
 342         packet_send();
 343 }
 344
 345 /*
 346  * Waits until the client can do something (some data becomes available on
 347  * one of the file descriptors).
 348  */
 349 static void
 350 client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp,
 351     int *maxfdp, u_int *nallocp, int rekeying)
 352 {
 353         struct timeval tv, *tvp;
 354         int ret;
 355
 356         /* Add any selections by the channel mechanism. */
 357         channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, rekeying);
 358
 359         if (!compat20) {
 360                 /* Read from the connection, unless our buffers are full. */
 361                 if (buffer_len(&stdout_buffer) < buffer_high &&
 362                     buffer_len(&stderr_buffer) < buffer_high &&
 363                     channel_not_very_much_buffered_data())
 364                         FD_SET(connection_in, *readsetp);
 365                 /*
 366                  * Read from stdin, unless we have seen EOF or have very much
 367                  * buffered data to send to the server.
 368                  */
 369                 if (!stdin_eof && packet_not_very_much_data_to_write())
 370                         FD_SET(fileno(stdin), *readsetp);
 371
 372                 /* Select stdout/stderr if have data in buffer. */
 373                 if (buffer_len(&stdout_buffer) > 0)
 374                         FD_SET(fileno(stdout), *writesetp);
 375                 if (buffer_len(&stderr_buffer) > 0)
 376                         FD_SET(fileno(stderr), *writesetp);
 377         } else {
 378                 /* channel_prepare_select could have closed the last channel */
 379                 if (session_closed && !channel_still_open() &&
 380                     !packet_have_data_to_write()) {
 381                         /* clear mask since we did not call select() */
 382                         memset(*readsetp, 0, *nallocp);
 383                         memset(*writesetp, 0, *nallocp);
 384                         return;
 385                 } else {
 386                         FD_SET(connection_in, *readsetp);
 387                 }
 388         }
 389
 390         /* Select server connection if have data to write to the server. */
 391         if (packet_have_data_to_write())
 392                 FD_SET(connection_out, *writesetp);
 393
 394         if (control_fd != -1)
 395                 FD_SET(control_fd, *readsetp);
 396
 397         /*
 398          * Wait for something to happen.  This will suspend the process until
 399          * some selected descriptor can be read, written, or has some other
 400          * event pending.
 401          */
 402
 403         if (options.server_alive_interval == 0 || !compat20)
 404                 tvp = NULL;
 405         else {
 406                 tv.tv_sec = options.server_alive_interval;
 407                 tv.tv_usec = 0;
 408                 tvp = &tv;
 409         }
 410         ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
 411         if (ret < 0) {
 412                 char buf[100];
 413
 414                 /*
 415                  * We have to clear the select masks, because we return.
 416                  * We have to return, because the mainloop checks for the flags
 417                  * set by the signal handlers.
 418                  */
 419                 memset(*readsetp, 0, *nallocp);
 420                 memset(*writesetp, 0, *nallocp);
 421
 422                 if (errno == EINTR)
 423                         return;
 424                 /* Note: we might still have data in the buffers. */
 425                 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno));
 426                 buffer_append(&stderr_buffer, buf, strlen(buf));
 427                 quit_pending = 1;
 428         } else if (ret == 0)
 429                 server_alive_check();
 430 }
 431
 432 static void
 433 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr)
 434 {
 435         /* Flush stdout and stderr buffers. */
 436         if (buffer_len(bout) > 0)
 437                 atomicio(vwrite, fileno(stdout), buffer_ptr(bout), buffer_len(bout));
 438         if (buffer_len(berr) > 0)
 439                 atomicio(vwrite, fileno(stderr), buffer_ptr(berr), buffer_len(berr));
 440
 441         leave_raw_mode();
 442
 443         /*
 444          * Free (and clear) the buffer to reduce the amount of data that gets
 445          * written to swap.
 446          */
 447         buffer_free(bin);
 448         buffer_free(bout);
 449         buffer_free(berr);
 450
 451         /* Send the suspend signal to the program itself. */
 452         kill(getpid(), SIGTSTP);
 453
 454         /* Reset window sizes in case they have changed */
 455         received_window_change_signal = 1;
 456
 457         /* OK, we have been continued by the user. Reinitialize buffers. */
 458         buffer_init(bin);
 459         buffer_init(bout);
 460         buffer_init(berr);
 461
 462         enter_raw_mode();
 463 }
 464
 465 static void
 466 client_process_net_input(fd_set * readset)
 467 {
 468         int len;
 469         char buf[8192];
 470
 471         /*
 472          * Read input from the server, and add any such data to the buffer of
 473          * the packet subsystem.
 474          */
 475         if (FD_ISSET(connection_in, readset)) {
 476                 /* Read as much as possible. */
 477                 len = read(connection_in, buf, sizeof(buf));
 478                 if (len == 0) {
 479                         /* Received EOF.  The remote host has closed the connection. */
 480                         snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n",
 481                                  host);
 482                         buffer_append(&stderr_buffer, buf, strlen(buf));
 483                         quit_pending = 1;
 484                         return;
 485                 }
 486                 /*
 487                  * There is a kernel bug on Solaris that causes select to
 488                  * sometimes wake up even though there is no data available.
 489                  */
 490                 if (len < 0 && (errno == EAGAIN || errno == EINTR))
 491                         len = 0;
 492
 493                 if (len < 0) {
 494                         /* An error has encountered.  Perhaps there is a network problem. */
 495                         snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n",
 496                                  host, strerror(errno));
 497                         buffer_append(&stderr_buffer, buf, strlen(buf));
 498                         quit_pending = 1;
 499                         return;
 500                 }
 501                 packet_process_incoming(buf, len);
 502         }
 503 }
 504
 505 static void
 506 client_subsystem_reply(int type, u_int32_t seq, void *ctxt)
 507 {
 508         int id;
 509         Channel *c;
 510
 511         id = packet_get_int();
 512         packet_check_eom();
 513
 514         if ((c = channel_lookup(id)) == NULL) {
 515                 error("%s: no channel for id %d", __func__, id);
 516                 return;
 517         }
 518
 519         if (type == SSH2_MSG_CHANNEL_SUCCESS)
 520                 debug2("Request suceeded on channel %d", id);
 521         else if (type == SSH2_MSG_CHANNEL_FAILURE) {
 522                 error("Request failed on channel %d", id);
 523                 channel_free(c);
 524         }
 525 }
 526
 527 static void
 528 client_extra_session2_setup(int id, void *arg)
 529 {
 530         struct confirm_ctx *cctx = arg;
 531         Channel *c;
 532         int i;
 533
 534         if (cctx == NULL)
 535                 fatal("%s: cctx == NULL", __func__);
 536         if ((c = channel_lookup(id)) == NULL)
 537                 fatal("%s: no channel for id %d", __func__, id);
 538
 539         client_session2_setup(id, cctx->want_tty, cctx->want_subsys,
 540             cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env,
 541             client_subsystem_reply);
 542
 543         c->confirm_ctx = NULL;
 544         buffer_free(&cctx->cmd);
 545         xfree(cctx->term);
 546         if (cctx->env != NULL) {
 547                 for (i = 0; cctx->env[i] != NULL; i++)
 548                         xfree(cctx->env[i]);
 549                 xfree(cctx->env);
 550         }
 551         xfree(cctx);
 552 }
 553
 554 static void
 555 client_process_control(fd_set * readset)
 556 {
 557         Buffer m;
 558         Channel *c;
 559         int client_fd, new_fd[3], ver, i, allowed;
 560         socklen_t addrlen;
 561         struct sockaddr_storage addr;
 562         struct confirm_ctx *cctx;
 563         char *cmd;
 564         u_int len, env_len, command, flags;
 565         uid_t euid;
 566         gid_t egid;
 567
 568         /*
 569          * Accept connection on control socket
 570          */
 571         if (control_fd == -1 || !FD_ISSET(control_fd, readset))
 572                 return;
 573
 574         memset(&addr, 0, sizeof(addr));
 575         addrlen = sizeof(addr);
 576         if ((client_fd = accept(control_fd,
 577             (struct sockaddr*)&addr, &addrlen)) == -1) {
 578                 error("%s accept: %s", __func__, strerror(errno));
 579                 return;
 580         }
 581
 582         if (getpeereid(client_fd, &euid, &egid) < 0) {
 583                 error("%s getpeereid failed: %s", __func__, strerror(errno));
 584                 close(client_fd);
 585                 return;
 586         }
 587         if ((euid != 0) && (getuid() != euid)) {
 588                 error("control mode uid mismatch: peer euid %u != uid %u",
 589                     (u_int) euid, (u_int) getuid());
 590                 close(client_fd);
 591                 return;
 592         }
 593
 594         unset_nonblock(client_fd);
 595
 596         /* Read command */
 597         buffer_init(&m);
 598         if (ssh_msg_recv(client_fd, &m) == -1) {
 599                 error("%s: client msg_recv failed", __func__);
 600                 close(client_fd);
 601                 buffer_free(&m);
 602                 return;
 603         }
 604         if ((ver = buffer_get_char(&m)) != 1) {
 605                 error("%s: wrong client version %d", __func__, ver);
 606                 buffer_free(&m);
 607                 close(client_fd);
 608                 return;
 609         }
 610
 611         allowed = 1;
 612         command = buffer_get_int(&m);
 613         flags = buffer_get_int(&m);
 614
 615         buffer_clear(&m);
 616
 617         switch (command) {
 618         case SSHMUX_COMMAND_OPEN:
 619                 if (options.control_master == SSHCTL_MASTER_ASK ||
 620                     options.control_master == SSHCTL_MASTER_AUTO_ASK)
 621                         allowed = ask_permission("Allow shared connection "
 622                             "to %s? ", host);
 623                 /* continue below */
 624                 break;
 625         case SSHMUX_COMMAND_TERMINATE:
 626                 if (options.control_master == SSHCTL_MASTER_ASK ||
 627                     options.control_master == SSHCTL_MASTER_AUTO_ASK)
 628                         allowed = ask_permission("Terminate shared connection "
 629                             "to %s? ", host);
 630                 if (allowed)
 631                         quit_pending = 1;
 632                 /* FALLTHROUGH */
 633         case SSHMUX_COMMAND_ALIVE_CHECK:
 634                 /* Reply for SSHMUX_COMMAND_TERMINATE and ALIVE_CHECK */
 635                 buffer_clear(&m);
 636                 buffer_put_int(&m, allowed);
 637                 buffer_put_int(&m, getpid());
 638                 if (ssh_msg_send(client_fd, /* version */1, &m) == -1) {
 639                         error("%s: client msg_send failed", __func__);
 640                         close(client_fd);
 641                         buffer_free(&m);
 642                         return;
 643                 }
 644                 buffer_free(&m);
 645                 close(client_fd);
 646                 return;
 647         default:
 648                 error("Unsupported command %d", command);
 649                 buffer_free(&m);
 650                 close(client_fd);
 651                 return;
 652         }
 653
 654         /* Reply for SSHMUX_COMMAND_OPEN */
 655         buffer_clear(&m);
 656         buffer_put_int(&m, allowed);
 657         buffer_put_int(&m, getpid());
 658         if (ssh_msg_send(client_fd, /* version */1, &m) == -1) {
 659                 error("%s: client msg_send failed", __func__);
 660                 close(client_fd);
 661                 buffer_free(&m);
 662                 return;
 663         }
 664
 665         if (!allowed) {
 666                 error("Refused control connection");
 667                 close(client_fd);
 668                 buffer_free(&m);
 669                 return;
 670         }
 671
 672         buffer_clear(&m);
 673         if (ssh_msg_recv(client_fd, &m) == -1) {
 674                 error("%s: client msg_recv failed", __func__);
 675                 close(client_fd);
 676                 buffer_free(&m);
 677                 return;
 678         }
 679         if ((ver = buffer_get_char(&m)) != 1) {
 680                 error("%s: wrong client version %d", __func__, ver);
 681                 buffer_free(&m);
 682                 close(client_fd);
 683                 return;
 684         }
 685
 686         cctx = xmalloc(sizeof(*cctx));
 687         memset(cctx, 0, sizeof(*cctx));
 688         cctx->want_tty = (flags & SSHMUX_FLAG_TTY) != 0;
 689         cctx->want_subsys = (flags & SSHMUX_FLAG_SUBSYS) != 0;
 690         cctx->term = buffer_get_string(&m, &len);
 691
 692         cmd = buffer_get_string(&m, &len);
 693         buffer_init(&cctx->cmd);
 694         buffer_append(&cctx->cmd, cmd, strlen(cmd));
 695
 696         env_len = buffer_get_int(&m);
 697         env_len = MIN(env_len, 4096);
 698         debug3("%s: receiving %d env vars", __func__, env_len);
 699         if (env_len != 0) {
 700                 cctx->env = xmalloc(sizeof(*cctx->env) * (env_len + 1));
 701                 for (i = 0; i < env_len; i++)
 702                         cctx->env[i] = buffer_get_string(&m, &len);
 703                 cctx->env[i] = NULL;
 704         }
 705
 706         debug2("%s: accepted tty %d, subsys %d, cmd %s", __func__,
 707             cctx->want_tty, cctx->want_subsys, cmd);
 708
 709         /* Gather fds from client */
 710         new_fd[0] = mm_receive_fd(client_fd);
 711         new_fd[1] = mm_receive_fd(client_fd);
 712         new_fd[2] = mm_receive_fd(client_fd);
 713
 714         debug2("%s: got fds stdin %d, stdout %d, stderr %d", __func__,
 715             new_fd[0], new_fd[1], new_fd[2]);
 716
 717         /* Try to pick up ttymodes from client before it goes raw */
 718         if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1)
 719                 error("%s: tcgetattr: %s", __func__, strerror(errno));
 720
 721         /* This roundtrip is just for synchronisation of ttymodes */
 722         buffer_clear(&m);
 723         if (ssh_msg_send(client_fd, /* version */1, &m) == -1) {
 724                 error("%s: client msg_send failed", __func__);
 725                 close(client_fd);
 726                 close(new_fd[0]);
 727                 close(new_fd[1]);
 728                 close(new_fd[2]);
 729                 buffer_free(&m);
 730                 xfree(cctx->term);
 731                 if (env_len != 0) {
 732                         for (i = 0; i < env_len; i++)
 733                                 xfree(cctx->env[i]);
 734                         xfree(cctx->env);
 735                 }
 736                 return;
 737         }
 738         buffer_free(&m);
 739
 740         /* enable nonblocking unless tty */
 741         if (!isatty(new_fd[0]))
 742                 set_nonblock(new_fd[0]);
 743         if (!isatty(new_fd[1]))
 744                 set_nonblock(new_fd[1]);
 745         if (!isatty(new_fd[2]))
 746                 set_nonblock(new_fd[2]);
 747
 748         set_nonblock(client_fd);
 749
 750         c = channel_new("session", SSH_CHANNEL_OPENING,
 751             new_fd[0], new_fd[1], new_fd[2],
 752             CHAN_SES_WINDOW_DEFAULT, CHAN_SES_PACKET_DEFAULT,
 753             CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0);
 754
 755         /* XXX */
 756         c->ctl_fd = client_fd;
 757
 758         debug3("%s: channel_new: %d", __func__, c->self);
 759
 760         channel_send_open(c->self);
 761         channel_register_confirm(c->self, client_extra_session2_setup, cctx);
 762 }
 763
 764 static void
 765 process_cmdline(void)
 766 {
 767         void (*handler)(int);
 768         char *s, *cmd, *cancel_host;
 769         int delete = 0;
 770         int local = 0;
 771         u_short cancel_port;
 772         Forward fwd;
 773
 774         leave_raw_mode();
 775         handler = signal(SIGINT, SIG_IGN);
 776         cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
 777         if (s == NULL)
 778                 goto out;
 779         while (*s && isspace(*s))
 780                 s++;
 781         if (*s == '-')
 782                 s++;    /* Skip cmdline '-', if any */
 783         if (*s == '\0')
 784                 goto out;
 785
 786         if (*s == 'h' || *s == 'H' || *s == '?') {
 787                 logit("Commands:");
 788                 logit("      -Lport:host:hostport    Request local forward");
 789                 logit("      -Rport:host:hostport    Request remote forward");
 790                 logit("      -KRhostport             Cancel remote forward");
 791                 goto out;
 792         }
 793
 794         if (*s == 'K') {
 795                 delete = 1;
 796                 s++;
 797         }
 798         if (*s != 'L' && *s != 'R') {
 799                 logit("Invalid command.");
 800                 goto out;
 801         }
 802         if (*s == 'L')
 803                 local = 1;
 804         if (local && delete) {
 805                 logit("Not supported.");
 806                 goto out;
 807         }
 808         if ((!local || delete) && !compat20) {
 809                 logit("Not supported for SSH protocol version 1.");
 810                 goto out;
 811         }
 812
 813         s++;
 814         while (*s && isspace(*s))
 815                 s++;
 816
 817         if (delete) {
 818                 cancel_port = 0;
 819                 cancel_host = hpdelim(&s);      /* may be NULL */
 820                 if (s != NULL) {
 821                         cancel_port = a2port(s);
 822                         cancel_host = cleanhostname(cancel_host);
 823                 } else {
 824                         cancel_port = a2port(cancel_host);
 825                         cancel_host = NULL;
 826                 }
 827                 if (cancel_port == 0) {
 828                         logit("Bad forwarding close port");
 829                         goto out;
 830                 }
 831                 channel_request_rforward_cancel(cancel_host, cancel_port);
 832         } else {
 833                 if (!parse_forward(&fwd, s)) {
 834                         logit("Bad forwarding specification.");
 835                         goto out;
 836                 }
 837                 if (local) {
 838                         if (channel_setup_local_fwd_listener(fwd.listen_host,
 839                             fwd.listen_port, fwd.connect_host,
 840                             fwd.connect_port, options.gateway_ports) < 0) {
 841                                 logit("Port forwarding failed.");
 842                                 goto out;
 843                         }
 844                 } else {
 845                         channel_request_remote_forwarding(fwd.listen_host,
 846                             fwd.listen_port, fwd.connect_host,
 847                             fwd.connect_port);
 848                 }
 849
 850                 logit("Forwarding port.");
 851         }
 852
 853 out:
 854         signal(SIGINT, handler);
 855         enter_raw_mode();
 856         if (cmd)
 857                 xfree(cmd);
 858 }
 859
 860 /* process the characters one by one */
 861 static int
 862 process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
 863 {
 864         char string[1024];
 865         pid_t pid;
 866         int bytes = 0;
 867         u_int i;
 868         u_char ch;
 869         char *s;
 870
 871         for (i = 0; i < len; i++) {
 872                 /* Get one character at a time. */
 873                 ch = buf[i];
 874
 875                 if (escape_pending) {
 876                         /* We have previously seen an escape character. */
 877                         /* Clear the flag now. */
 878                         escape_pending = 0;
 879
 880                         /* Process the escaped character. */
 881                         switch (ch) {
 882                         case '.':
 883                                 /* Terminate the connection. */
 884                                 snprintf(string, sizeof string, "%c.\r\n", escape_char);
 885                                 buffer_append(berr, string, strlen(string));
 886
 887                                 quit_pending = 1;
 888                                 return -1;
 889
 890                         case 'Z' - 64:
 891                                 /* Suspend the program. */
 892                                 /* Print a message to that effect to the user. */
 893                                 snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char);
 894                                 buffer_append(berr, string, strlen(string));
 895
 896                                 /* Restore terminal modes and suspend. */
 897                                 client_suspend_self(bin, bout, berr);
 898
 899                                 /* We have been continued. */
 900                                 continue;
 901
 902                         case 'B':
 903                                 if (compat20) {
 904                                         snprintf(string, sizeof string,
 905                                             "%cB\r\n", escape_char);
 906                                         buffer_append(berr, string,
 907                                             strlen(string));
 908                                         channel_request_start(session_ident,
 909                                             "break", 0);
 910                                         packet_put_int(1000);
 911                                         packet_send();
 912                                 }
 913                                 continue;
 914
 915                         case 'R':
 916                                 if (compat20) {
 917                                         if (datafellows & SSH_BUG_NOREKEY)
 918                                                 logit("Server does not support re-keying");
 919                                         else
 920                                                 need_rekeying = 1;
 921                                 }
 922                                 continue;
 923
 924                         case '&':
 925                                 /*
 926                                  * Detach the program (continue to serve connections,
 927                                  * but put in background and no more new connections).
 928                                  */
 929                                 /* Restore tty modes. */
 930                                 leave_raw_mode();
 931
 932                                 /* Stop listening for new connections. */
 933                                 channel_stop_listening();
 934
 935                                 snprintf(string, sizeof string,
 936                                     "%c& [backgrounded]\n", escape_char);
 937                                 buffer_append(berr, string, strlen(string));
 938
 939                                 /* Fork into background. */
 940                                 pid = fork();
 941                                 if (pid < 0) {
 942                                         error("fork: %.100s", strerror(errno));
 943                                         continue;
 944                                 }
 945                                 if (pid != 0) { /* This is the parent. */
 946                                         /* The parent just exits. */
 947                                         exit(0);
 948                                 }
 949                                 /* The child continues serving connections. */
 950                                 if (compat20) {
 951                                         buffer_append(bin, "\004", 1);
 952                                         /* fake EOF on stdin */
 953                                         return -1;
 954                                 } else if (!stdin_eof) {
 955                                         /*
 956                                          * Sending SSH_CMSG_EOF alone does not always appear
 957                                          * to be enough.  So we try to send an EOF character
 958                                          * first.
 959                                          */
 960                                         packet_start(SSH_CMSG_STDIN_DATA);
 961                                         packet_put_string("\004", 1);
 962                                         packet_send();
 963                                         /* Close stdin. */
 964                                         stdin_eof = 1;
 965                                         if (buffer_len(bin) == 0) {
 966                                                 packet_start(SSH_CMSG_EOF);
 967                                                 packet_send();
 968                                         }
 969                                 }
 970                                 continue;
 971
 972                         case '?':
 973                                 snprintf(string, sizeof string,
 974 "%c?\r\n\
 975 Supported escape sequences:\r\n\
 976 %c.  - terminate connection\r\n\
 977 %cB  - send a BREAK to the remote system\r\n\
 978 %cC  - open a command line\r\n\
 979 %cR  - Request rekey (SSH protocol 2 only)\r\n\
 980 %c^Z - suspend ssh\r\n\
 981 %c#  - list forwarded connections\r\n\
 982 %c&  - background ssh (when waiting for connections to terminate)\r\n\
 983 %c?  - this message\r\n\
 984 %c%c  - send the escape character by typing it twice\r\n\
 985 (Note that escapes are only recognized immediately after newline.)\r\n",
 986                                     escape_char, escape_char, escape_char, escape_char,
 987                                     escape_char, escape_char, escape_char, escape_char,
 988                                     escape_char, escape_char, escape_char);
 989                                 buffer_append(berr, string, strlen(string));
 990                                 continue;
 991
 992                         case '#':
 993                                 snprintf(string, sizeof string, "%c#\r\n", escape_char);
 994                                 buffer_append(berr, string, strlen(string));
 995                                 s = channel_open_message();
 996                                 buffer_append(berr, s, strlen(s));
 997                                 xfree(s);
 998                                 continue;
 999
1000                         case 'C':
1001                                 process_cmdline();
1002                                 continue;
1003
1004                         default:
1005                                 if (ch != escape_char) {
1006                                         buffer_put_char(bin, escape_char);
1007                                         bytes++;
1008                                 }
1009                                 /* Escaped characters fall through here */
1010                                 break;
1011                         }
1012                 } else {
1013                         /*
1014                          * The previous character was not an escape char. Check if this
1015                          * is an escape.
1016                          */
1017                         if (last_was_cr && ch == escape_char) {
1018                                 /* It is. Set the flag and continue to next character. */
1019                                 escape_pending = 1;
1020                                 continue;
1021                         }
1022                 }
1023
1024                 /*
1025                  * Normal character.  Record whether it was a newline,
1026                  * and append it to the buffer.
1027                  */
1028                 last_was_cr = (ch == '\r' || ch == '\n');
1029                 buffer_put_char(bin, ch);
1030                 bytes++;
1031         }
1032         return bytes;
1033 }
1034
1035 static void
1036 client_process_input(fd_set * readset)
1037 {
1038         int len;
1039         char buf[8192];
1040
1041         /* Read input from stdin. */
1042         if (FD_ISSET(fileno(stdin), readset)) {
1043                 /* Read as much as possible. */
1044                 len = read(fileno(stdin), buf, sizeof(buf));
1045                 if (len < 0 && (errno == EAGAIN || errno == EINTR))
1046                         return;         /* we'll try again later */
1047                 if (len <= 0) {
1048                         /*
1049                          * Received EOF or error.  They are treated
1050                          * similarly, except that an error message is printed
1051                          * if it was an error condition.
1052                          */
1053                         if (len < 0) {
1054                                 snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno));
1055                                 buffer_append(&stderr_buffer, buf, strlen(buf));
1056                         }
1057                         /* Mark that we have seen EOF. */
1058                         stdin_eof = 1;
1059                         /*
1060                          * Send an EOF message to the server unless there is
1061                          * data in the buffer.  If there is data in the
1062                          * buffer, no message will be sent now.  Code
1063                          * elsewhere will send the EOF when the buffer
1064                          * becomes empty if stdin_eof is set.
1065                          */
1066                         if (buffer_len(&stdin_buffer) == 0) {
1067                                 packet_start(SSH_CMSG_EOF);
1068                                 packet_send();
1069                         }
1070                 } else if (escape_char == SSH_ESCAPECHAR_NONE) {
1071                         /*
1072                          * Normal successful read, and no escape character.
1073                          * Just append the data to buffer.
1074                          */
1075                         buffer_append(&stdin_buffer, buf, len);
1076                 } else {
1077                         /*
1078                          * Normal, successful read.  But we have an escape character
1079                          * and have to process the characters one by one.
1080                          */
1081                         if (process_escapes(&stdin_buffer, &stdout_buffer,
1082                             &stderr_buffer, buf, len) == -1)
1083                                 return;
1084                 }
1085         }
1086 }
1087
1088 static void
1089 client_process_output(fd_set * writeset)
1090 {
1091         int len;
1092         char buf[100];
1093
1094         /* Write buffered output to stdout. */
1095         if (FD_ISSET(fileno(stdout), writeset)) {
1096                 /* Write as much data as possible. */
1097                 len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1098                     buffer_len(&stdout_buffer));
1099                 if (len <= 0) {
1100                         if (errno == EINTR || errno == EAGAIN)
1101                                 len = 0;
1102                         else {
1103                                 /*
1104                                  * An error or EOF was encountered.  Put an
1105                                  * error message to stderr buffer.
1106                                  */
1107                                 snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno));
1108                                 buffer_append(&stderr_buffer, buf, strlen(buf));
1109                                 quit_pending = 1;
1110                                 return;
1111                         }
1112                 }
1113                 /* Consume printed data from the buffer. */
1114                 buffer_consume(&stdout_buffer, len);
1115                 stdout_bytes += len;
1116         }
1117         /* Write buffered output to stderr. */
1118         if (FD_ISSET(fileno(stderr), writeset)) {
1119                 /* Write as much data as possible. */
1120                 len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1121                     buffer_len(&stderr_buffer));
1122                 if (len <= 0) {
1123                         if (errno == EINTR || errno == EAGAIN)
1124                                 len = 0;
1125                         else {
1126                                 /* EOF or error, but can't even print error message. */
1127                                 quit_pending = 1;
1128                                 return;
1129                         }
1130                 }
1131                 /* Consume printed characters from the buffer. */
1132                 buffer_consume(&stderr_buffer, len);
1133                 stderr_bytes += len;
1134         }
1135 }
1136
1137 /*
1138  * Get packets from the connection input buffer, and process them as long as
1139  * there are packets available.
1140  *
1141  * Any unknown packets received during the actual
1142  * session cause the session to terminate.  This is
1143  * intended to make debugging easier since no
1144  * confirmations are sent.  Any compatible protocol
1145  * extensions must be negotiated during the
1146  * preparatory phase.
1147  */
1148
1149 static void
1150 client_process_buffered_input_packets(void)
1151 {
1152         dispatch_run(DISPATCH_NONBLOCK, &quit_pending, compat20 ? xxx_kex : NULL);
1153 }
1154
1155 /* scan buf[] for '~' before sending data to the peer */
1156
1157 static int
1158 simple_escape_filter(Channel *c, char *buf, int len)
1159 {
1160         /* XXX we assume c->extended is writeable */
1161         return process_escapes(&c->input, &c->output, &c->extended, buf, len);
1162 }
1163
1164 static void
1165 client_channel_closed(int id, void *arg)
1166 {
1167         channel_cancel_cleanup(id);
1168         session_closed = 1;
1169         leave_raw_mode();
1170 }
1171
1172 /*
1173  * Implements the interactive session with the server.  This is called after
1174  * the user has been authenticated, and a command has been started on the
1175  * remote host.  If escape_char != SSH_ESCAPECHAR_NONE, it is the character
1176  * used as an escape character for terminating or suspending the session.
1177  */
1178
1179 int
1180 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
1181 {
1182         fd_set *readset = NULL, *writeset = NULL;
1183         double start_time, total_time;
1184         int max_fd = 0, max_fd2 = 0, len, rekeying = 0;
1185         u_int nalloc = 0;
1186         char buf[100];
1187
1188         debug("Entering interactive session.");
1189
1190         start_time = get_current_time();
1191
1192         /* Initialize variables. */
1193         escape_pending = 0;
1194         last_was_cr = 1;
1195         exit_status = -1;
1196         stdin_eof = 0;
1197         buffer_high = 64 * 1024;
1198         connection_in = packet_get_connection_in();
1199         connection_out = packet_get_connection_out();
1200         max_fd = MAX(connection_in, connection_out);
1201         if (control_fd != -1)
1202                 max_fd = MAX(max_fd, control_fd);
1203
1204         if (!compat20) {
1205                 /* enable nonblocking unless tty */
1206                 if (!isatty(fileno(stdin)))
1207                         set_nonblock(fileno(stdin));
1208                 if (!isatty(fileno(stdout)))
1209                         set_nonblock(fileno(stdout));
1210                 if (!isatty(fileno(stderr)))
1211                         set_nonblock(fileno(stderr));
1212                 max_fd = MAX(max_fd, fileno(stdin));
1213                 max_fd = MAX(max_fd, fileno(stdout));
1214                 max_fd = MAX(max_fd, fileno(stderr));
1215         }
1216         stdin_bytes = 0;
1217         stdout_bytes = 0;
1218         stderr_bytes = 0;
1219         quit_pending = 0;
1220         escape_char = escape_char_arg;
1221
1222         /* Initialize buffers. */
1223         buffer_init(&stdin_buffer);
1224         buffer_init(&stdout_buffer);
1225         buffer_init(&stderr_buffer);
1226
1227         client_init_dispatch();
1228
1229         /*
1230          * Set signal handlers, (e.g. to restore non-blocking mode)
1231          * but don't overwrite SIG_IGN, matches behaviour from rsh(1)
1232          */
1233         if (signal(SIGHUP, SIG_IGN) != SIG_IGN)
1234                 signal(SIGHUP, signal_handler);
1235         if (signal(SIGINT, SIG_IGN) != SIG_IGN)
1236                 signal(SIGINT, signal_handler);
1237         if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
1238                 signal(SIGQUIT, signal_handler);
1239         if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
1240                 signal(SIGTERM, signal_handler);
1241         signal(SIGWINCH, window_change_handler);
1242
1243         if (have_pty)
1244                 enter_raw_mode();
1245
1246         if (compat20) {
1247                 session_ident = ssh2_chan_id;
1248                 if (escape_char != SSH_ESCAPECHAR_NONE)
1249                         channel_register_filter(session_ident,
1250                             simple_escape_filter);
1251                 if (session_ident != -1)
1252                         channel_register_cleanup(session_ident,
1253                             client_channel_closed);
1254         } else {
1255                 /* Check if we should immediately send eof on stdin. */
1256                 client_check_initial_eof_on_stdin();
1257         }
1258
1259         /* Main loop of the client for the interactive session mode. */
1260         while (!quit_pending) {
1261
1262                 /* Process buffered packets sent by the server. */
1263                 client_process_buffered_input_packets();
1264
1265                 if (compat20 && session_closed && !channel_still_open())
1266                         break;
1267
1268                 rekeying = (xxx_kex != NULL && !xxx_kex->done);
1269
1270                 if (rekeying) {
1271                         debug("rekeying in progress");
1272                 } else {
1273                         /*
1274                          * Make packets of buffered stdin data, and buffer
1275                          * them for sending to the server.
1276                          */
1277                         if (!compat20)
1278                                 client_make_packets_from_stdin_data();
1279
1280                         /*
1281                          * Make packets from buffered channel data, and
1282                          * enqueue them for sending to the server.
1283                          */
1284                         if (packet_not_very_much_data_to_write())
1285                                 channel_output_poll();
1286
1287                         /*
1288                          * Check if the window size has changed, and buffer a
1289                          * message about it to the server if so.
1290                          */
1291                         client_check_window_change();
1292
1293                         if (quit_pending)
1294                                 break;
1295                 }
1296                 /*
1297                  * Wait until we have something to do (something becomes
1298                  * available on one of the descriptors).
1299                  */
1300                 max_fd2 = max_fd;
1301                 client_wait_until_can_do_something(&readset, &writeset,
1302                     &max_fd2, &nalloc, rekeying);
1303
1304                 if (quit_pending)
1305                         break;
1306
1307                 /* Do channel operations unless rekeying in progress. */
1308                 if (!rekeying) {
1309                         channel_after_select(readset, writeset);
1310                         if (need_rekeying || packet_need_rekeying()) {
1311                                 debug("need rekeying");
1312                                 xxx_kex->done = 0;
1313                                 kex_send_kexinit(xxx_kex);
1314                                 need_rekeying = 0;
1315                         }
1316                 }
1317
1318                 /* Buffer input from the connection.  */
1319                 client_process_net_input(readset);
1320
1321                 /* Accept control connections.  */
1322                 client_process_control(readset);
1323
1324                 if (quit_pending)
1325                         break;
1326
1327                 if (!compat20) {
1328                         /* Buffer data from stdin */
1329                         client_process_input(readset);
1330                         /*
1331                          * Process output to stdout and stderr.  Output to
1332                          * the connection is processed elsewhere (above).
1333                          */
1334                         client_process_output(writeset);
1335                 }
1336
1337                 /* Send as much buffered packet data as possible to the sender. */
1338                 if (FD_ISSET(connection_out, writeset))
1339                         packet_write_poll();
1340         }
1341         if (readset)
1342                 xfree(readset);
1343         if (writeset)
1344                 xfree(writeset);
1345
1346         /* Terminate the session. */
1347
1348         /* Stop watching for window change. */
1349         signal(SIGWINCH, SIG_DFL);
1350
1351         channel_free_all();
1352
1353         if (have_pty)
1354                 leave_raw_mode();
1355
1356         /* restore blocking io */
1357         if (!isatty(fileno(stdin)))
1358                 unset_nonblock(fileno(stdin));
1359         if (!isatty(fileno(stdout)))
1360                 unset_nonblock(fileno(stdout));
1361         if (!isatty(fileno(stderr)))
1362                 unset_nonblock(fileno(stderr));
1363
1364         /*
1365          * If there was no shell or command requested, there will be no remote
1366          * exit status to be returned.  In that case, clear error code if the
1367          * connection was deliberately terminated at this end.
1368          */
1369         if (no_shell_flag && received_signal == SIGTERM) {
1370                 received_signal = 0;
1371                 exit_status = 0;
1372         }
1373
1374         if (received_signal)
1375                 fatal("Killed by signal %d.", (int) received_signal);
1376
1377         /*
1378          * In interactive mode (with pseudo tty) display a message indicating
1379          * that the connection has been closed.
1380          */
1381         if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
1382                 snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host);
1383                 buffer_append(&stderr_buffer, buf, strlen(buf));
1384         }
1385
1386         /* Output any buffered data for stdout. */
1387         while (buffer_len(&stdout_buffer) > 0) {
1388                 len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1389                     buffer_len(&stdout_buffer));
1390                 if (len <= 0) {
1391                         error("Write failed flushing stdout buffer.");
1392                         break;
1393                 }
1394                 buffer_consume(&stdout_buffer, len);
1395                 stdout_bytes += len;
1396         }
1397
1398         /* Output any buffered data for stderr. */
1399         while (buffer_len(&stderr_buffer) > 0) {
1400                 len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1401                     buffer_len(&stderr_buffer));
1402                 if (len <= 0) {
1403                         error("Write failed flushing stderr buffer.");
1404                         break;
1405                 }
1406                 buffer_consume(&stderr_buffer, len);
1407                 stderr_bytes += len;
1408         }
1409
1410         /* Clear and free any buffers. */
1411         memset(buf, 0, sizeof(buf));
1412         buffer_free(&stdin_buffer);
1413         buffer_free(&stdout_buffer);
1414         buffer_free(&stderr_buffer);
1415
1416         /* Report bytes transferred, and transfer rates. */
1417         total_time = get_current_time() - start_time;
1418         debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
1419             stdin_bytes, stdout_bytes, stderr_bytes, total_time);
1420         if (total_time > 0)
1421                 debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
1422                     stdin_bytes / total_time, stdout_bytes / total_time,
1423                     stderr_bytes / total_time);
1424
1425         /* Return the exit status of the program. */
1426         debug("Exit status %d", exit_status);
1427         return exit_status;
1428 }
1429
1430 /*********/
1431
1432 static void
1433 client_input_stdout_data(int type, u_int32_t seq, void *ctxt)
1434 {
1435         u_int data_len;
1436         char *data = packet_get_string(&data_len);
1437         packet_check_eom();
1438         buffer_append(&stdout_buffer, data, data_len);
1439         memset(data, 0, data_len);
1440         xfree(data);
1441 }
1442 static void
1443 client_input_stderr_data(int type, u_int32_t seq, void *ctxt)
1444 {
1445         u_int data_len;
1446         char *data = packet_get_string(&data_len);
1447         packet_check_eom();
1448         buffer_append(&stderr_buffer, data, data_len);
1449         memset(data, 0, data_len);
1450         xfree(data);
1451 }
1452 static void
1453 client_input_exit_status(int type, u_int32_t seq, void *ctxt)
1454 {
1455         exit_status = packet_get_int();
1456         packet_check_eom();
1457         /* Acknowledge the exit. */
1458         packet_start(SSH_CMSG_EXIT_CONFIRMATION);
1459         packet_send();
1460         /*
1461          * Must wait for packet to be sent since we are
1462          * exiting the loop.
1463          */
1464         packet_write_wait();
1465         /* Flag that we want to exit. */
1466         quit_pending = 1;
1467 }
1468 static void
1469 client_input_agent_open(int type, u_int32_t seq, void *ctxt)
1470 {
1471         Channel *c = NULL;
1472         int remote_id, sock;
1473
1474         /* Read the remote channel number from the message. */
1475         remote_id = packet_get_int();
1476         packet_check_eom();
1477
1478         /*
1479          * Get a connection to the local authentication agent (this may again
1480          * get forwarded).
1481          */
1482         sock = ssh_get_authentication_socket();
1483
1484         /*
1485          * If we could not connect the agent, send an error message back to
1486          * the server. This should never happen unless the agent dies,
1487          * because authentication forwarding is only enabled if we have an
1488          * agent.
1489          */
1490         if (sock >= 0) {
1491                 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
1492                     -1, 0, 0, 0, "authentication agent connection", 1);
1493                 c->remote_id = remote_id;
1494                 c->force_drain = 1;
1495         }
1496         if (c == NULL) {
1497                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1498                 packet_put_int(remote_id);
1499         } else {
1500                 /* Send a confirmation to the remote host. */
1501                 debug("Forwarding authentication connection.");
1502                 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1503                 packet_put_int(remote_id);
1504                 packet_put_int(c->self);
1505         }
1506         packet_send();
1507 }
1508
1509 static Channel *
1510 client_request_forwarded_tcpip(const char *request_type, int rchan)
1511 {
1512         Channel *c = NULL;
1513         char *listen_address, *originator_address;
1514         int listen_port, originator_port;
1515         int sock;
1516
1517         /* Get rest of the packet */
1518         listen_address = packet_get_string(NULL);
1519         listen_port = packet_get_int();
1520         originator_address = packet_get_string(NULL);
1521         originator_port = packet_get_int();
1522         packet_check_eom();
1523
1524         debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d",
1525             listen_address, listen_port, originator_address, originator_port);
1526
1527         sock = channel_connect_by_listen_address(listen_port);
1528         if (sock < 0) {
1529                 xfree(originator_address);
1530                 xfree(listen_address);
1531                 return NULL;
1532         }
1533         c = channel_new("forwarded-tcpip",
1534             SSH_CHANNEL_CONNECTING, sock, sock, -1,
1535             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
1536             originator_address, 1);
1537         xfree(originator_address);
1538         xfree(listen_address);
1539         return c;
1540 }
1541
1542 static Channel *
1543 client_request_x11(const char *request_type, int rchan)
1544 {
1545         Channel *c = NULL;
1546         char *originator;
1547         int originator_port;
1548         int sock;
1549
1550         if (!options.forward_x11) {
1551                 error("Warning: ssh server tried X11 forwarding.");
1552                 error("Warning: this is probably a break in attempt by a malicious server.");
1553                 return NULL;
1554         }
1555         originator = packet_get_string(NULL);
1556         if (datafellows & SSH_BUG_X11FWD) {
1557                 debug2("buggy server: x11 request w/o originator_port");
1558                 originator_port = 0;
1559         } else {
1560                 originator_port = packet_get_int();
1561         }
1562         packet_check_eom();
1563         /* XXX check permission */
1564         debug("client_request_x11: request from %s %d", originator,
1565             originator_port);
1566         xfree(originator);
1567         sock = x11_connect_display();
1568         if (sock < 0)
1569                 return NULL;
1570         c = channel_new("x11",
1571             SSH_CHANNEL_X11_OPEN, sock, sock, -1,
1572             CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1);
1573         c->force_drain = 1;
1574         return c;
1575 }
1576
1577 static Channel *
1578 client_request_agent(const char *request_type, int rchan)
1579 {
1580         Channel *c = NULL;
1581         int sock;
1582
1583         if (!options.forward_agent) {
1584                 error("Warning: ssh server tried agent forwarding.");
1585                 error("Warning: this is probably a break in attempt by a malicious server.");
1586                 return NULL;
1587         }
1588         sock =  ssh_get_authentication_socket();
1589         if (sock < 0)
1590                 return NULL;
1591         c = channel_new("authentication agent connection",
1592             SSH_CHANNEL_OPEN, sock, sock, -1,
1593             CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
1594             "authentication agent connection", 1);
1595         c->force_drain = 1;
1596         return c;
1597 }
1598
1599 /* XXXX move to generic input handler */
1600 static void
1601 client_input_channel_open(int type, u_int32_t seq, void *ctxt)
1602 {
1603         Channel *c = NULL;
1604         char *ctype;
1605         int rchan;
1606         u_int rmaxpack, rwindow, len;
1607
1608         ctype = packet_get_string(&len);
1609         rchan = packet_get_int();
1610         rwindow = packet_get_int();
1611         rmaxpack = packet_get_int();
1612
1613         debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
1614             ctype, rchan, rwindow, rmaxpack);
1615
1616         if (strcmp(ctype, "forwarded-tcpip") == 0) {
1617                 c = client_request_forwarded_tcpip(ctype, rchan);
1618         } else if (strcmp(ctype, "x11") == 0) {
1619                 c = client_request_x11(ctype, rchan);
1620         } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) {
1621                 c = client_request_agent(ctype, rchan);
1622         }
1623 /* XXX duplicate : */
1624         if (c != NULL) {
1625                 debug("confirm %s", ctype);
1626                 c->remote_id = rchan;
1627                 c->remote_window = rwindow;
1628                 c->remote_maxpacket = rmaxpack;
1629                 if (c->type != SSH_CHANNEL_CONNECTING) {
1630                         packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1631                         packet_put_int(c->remote_id);
1632                         packet_put_int(c->self);
1633                         packet_put_int(c->local_window);
1634                         packet_put_int(c->local_maxpacket);
1635                         packet_send();
1636                 }
1637         } else {
1638                 debug("failure %s", ctype);
1639                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1640                 packet_put_int(rchan);
1641                 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1642                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1643                         packet_put_cstring("open failed");
1644                         packet_put_cstring("");
1645                 }
1646                 packet_send();
1647         }
1648         xfree(ctype);
1649 }
1650 static void
1651 client_input_channel_req(int type, u_int32_t seq, void *ctxt)
1652 {
1653         Channel *c = NULL;
1654         int exitval, id, reply, success = 0;
1655         char *rtype;
1656
1657         id = packet_get_int();
1658         rtype = packet_get_string(NULL);
1659         reply = packet_get_char();
1660
1661         debug("client_input_channel_req: channel %d rtype %s reply %d",
1662             id, rtype, reply);
1663
1664         if (id == -1) {
1665                 error("client_input_channel_req: request for channel -1");
1666         } else if ((c = channel_lookup(id)) == NULL) {
1667                 error("client_input_channel_req: channel %d: unknown channel", id);
1668         } else if (strcmp(rtype, "exit-status") == 0) {
1669                 exitval = packet_get_int();
1670                 if (id == session_ident) {
1671                         success = 1;
1672                         exit_status = exitval;
1673                 } else if (c->ctl_fd == -1) {
1674                         error("client_input_channel_req: unexpected channel %d",
1675                             session_ident);
1676                 } else {
1677                         atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval));
1678                         success = 1;
1679                 }
1680                 packet_check_eom();
1681         }
1682         if (reply) {
1683                 packet_start(success ?
1684                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1685                 packet_put_int(id);
1686                 packet_send();
1687         }
1688         xfree(rtype);
1689 }
1690 static void
1691 client_input_global_request(int type, u_int32_t seq, void *ctxt)
1692 {
1693         char *rtype;
1694         int want_reply;
1695         int success = 0;
1696
1697         rtype = packet_get_string(NULL);
1698         want_reply = packet_get_char();
1699         debug("client_input_global_request: rtype %s want_reply %d",
1700             rtype, want_reply);
1701         if (want_reply) {
1702                 packet_start(success ?
1703                     SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1704                 packet_send();
1705                 packet_write_wait();
1706         }
1707         xfree(rtype);
1708 }
1709
1710 void
1711 client_session2_setup(int id, int want_tty, int want_subsystem,
1712     const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env,
1713     dispatch_fn *subsys_repl)
1714 {
1715         int len;
1716         Channel *c = NULL;
1717
1718         debug2("%s: id %d", __func__, id);
1719
1720         if ((c = channel_lookup(id)) == NULL)
1721                 fatal("client_session2_setup: channel %d: unknown channel", id);
1722
1723         if (want_tty) {
1724                 struct winsize ws;
1725                 struct termios tio;
1726
1727                 /* Store window size in the packet. */
1728                 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0)
1729                         memset(&ws, 0, sizeof(ws));
1730
1731                 channel_request_start(id, "pty-req", 0);
1732                 packet_put_cstring(term != NULL ? term : "");
1733                 packet_put_int(ws.ws_col);
1734                 packet_put_int(ws.ws_row);
1735                 packet_put_int(ws.ws_xpixel);
1736                 packet_put_int(ws.ws_ypixel);
1737                 tio = get_saved_tio();
1738                 tty_make_modes(-1, tiop != NULL ? tiop : &tio);
1739                 packet_send();
1740                 /* XXX wait for reply */
1741                 c->client_tty = 1;
1742         }
1743
1744         /* Transfer any environment variables from client to server */
1745         if (options.num_send_env != 0 && env != NULL) {
1746                 int i, j, matched;
1747                 char *name, *val;
1748
1749                 debug("Sending environment.");
1750                 for (i = 0; env[i] != NULL; i++) {
1751                         /* Split */
1752                         name = xstrdup(env[i]);
1753                         if ((val = strchr(name, '=')) == NULL) {
1754                                 free(name);
1755                                 continue;
1756                         }
1757                         *val++ = '\0';
1758
1759                         matched = 0;
1760                         for (j = 0; j < options.num_send_env; j++) {
1761                                 if (match_pattern(name, options.send_env[j])) {
1762                                         matched = 1;
1763                                         break;
1764                                 }
1765                         }
1766                         if (!matched) {
1767                                 debug3("Ignored env %s", name);
1768                                 free(name);
1769                                 continue;
1770                         }
1771
1772                         debug("Sending env %s = %s", name, val);
1773                         channel_request_start(id, "env", 0);
1774                         packet_put_cstring(name);
1775                         packet_put_cstring(val);
1776                         packet_send();
1777                         free(name);
1778                 }
1779         }
1780
1781         len = buffer_len(cmd);
1782         if (len > 0) {
1783                 if (len > 900)
1784                         len = 900;
1785                 if (want_subsystem) {
1786                         debug("Sending subsystem: %.*s", len, (u_char*)buffer_ptr(cmd));
1787                         channel_request_start(id, "subsystem", subsys_repl != NULL);
1788                         if (subsys_repl != NULL) {
1789                                 /* register callback for reply */
1790                                 /* XXX we assume that client_loop has already been called */
1791                                 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, subsys_repl);
1792                                 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, subsys_repl);
1793                         }
1794                 } else {
1795                         debug("Sending command: %.*s", len, (u_char*)buffer_ptr(cmd));
1796                         channel_request_start(id, "exec", 0);
1797                 }
1798                 packet_put_string(buffer_ptr(cmd), buffer_len(cmd));
1799                 packet_send();
1800         } else {
1801                 channel_request_start(id, "shell", 0);
1802                 packet_send();
1803         }
1804 }
1805
1806 static void
1807 client_init_dispatch_20(void)
1808 {
1809         dispatch_init(&dispatch_protocol_error);
1810
1811         dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1812         dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1813         dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1814         dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1815         dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
1816         dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1817         dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1818         dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
1819         dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1820         dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);
1821
1822         /* rekeying */
1823         dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1824
1825         /* global request reply messages */
1826         dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
1827         dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
1828 }
1829 static void
1830 client_init_dispatch_13(void)
1831 {
1832         dispatch_init(NULL);
1833         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1834         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1835         dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1836         dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1837         dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1838         dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1839         dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
1840         dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
1841         dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);
1842
1843         dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ?
1844             &client_input_agent_open : &deny_input_open);
1845         dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ?
1846             &x11_input_open : &deny_input_open);
1847 }
1848 static void
1849 client_init_dispatch_15(void)
1850 {
1851         client_init_dispatch_13();
1852         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1853         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
1854 }
1855 static void
1856 client_init_dispatch(void)
1857 {
1858         if (compat20)
1859                 client_init_dispatch_20();
1860         else if (compat13)
1861                 client_init_dispatch_13();
1862         else
1863                 client_init_dispatch_15();
1864 }
1865
1866 /* client specific fatal cleanup */
1867 void
1868 cleanup_exit(int i)
1869 {
1870         leave_raw_mode();
1871         leave_non_blocking();
1872         if (options.control_path != NULL && control_fd != -1)
1873                 unlink(options.control_path);
1874         _exit(i);
1875 }