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 1.134 2004/11/07 00:01:46 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 == 2)
 620                         allowed = ask_permission("Allow shared connection "
 621                             "to %s? ", host);
 622                 /* continue below */
 623                 break;
 624         case SSHMUX_COMMAND_TERMINATE:
 625                 if (options.control_master == 2)
 626                         allowed = ask_permission("Terminate shared connection "
 627                             "to %s? ", host);
 628                 if (allowed)
 629                         quit_pending = 1;
 630                 /* FALLTHROUGH */
 631         case SSHMUX_COMMAND_ALIVE_CHECK:
 632                 /* Reply for SSHMUX_COMMAND_TERMINATE and ALIVE_CHECK */
 633                 buffer_clear(&m);
 634                 buffer_put_int(&m, allowed);
 635                 buffer_put_int(&m, getpid());
 636                 if (ssh_msg_send(client_fd, /* version */1, &m) == -1) {
 637                         error("%s: client msg_send failed", __func__);
 638                         close(client_fd);
 639                         buffer_free(&m);
 640                         return;
 641                 }
 642                 buffer_free(&m);
 643                 close(client_fd);
 644                 return;
 645         default:
 646                 error("Unsupported command %d", command);
 647                 buffer_free(&m);
 648                 close(client_fd);
 649                 return;
 650         }
 651
 652         /* Reply for SSHMUX_COMMAND_OPEN */
 653         buffer_clear(&m);
 654         buffer_put_int(&m, allowed);
 655         buffer_put_int(&m, getpid());
 656         if (ssh_msg_send(client_fd, /* version */1, &m) == -1) {
 657                 error("%s: client msg_send failed", __func__);
 658                 close(client_fd);
 659                 buffer_free(&m);
 660                 return;
 661         }
 662
 663         if (!allowed) {
 664                 error("Refused control connection");
 665                 close(client_fd);
 666                 buffer_free(&m);
 667                 return;
 668         }
 669
 670         buffer_clear(&m);
 671         if (ssh_msg_recv(client_fd, &m) == -1) {
 672                 error("%s: client msg_recv failed", __func__);
 673                 close(client_fd);
 674                 buffer_free(&m);
 675                 return;
 676         }
 677         if ((ver = buffer_get_char(&m)) != 1) {
 678                 error("%s: wrong client version %d", __func__, ver);
 679                 buffer_free(&m);
 680                 close(client_fd);
 681                 return;
 682         }
 683
 684         cctx = xmalloc(sizeof(*cctx));
 685         memset(cctx, 0, sizeof(*cctx));
 686         cctx->want_tty = (flags & SSHMUX_FLAG_TTY) != 0;
 687         cctx->want_subsys = (flags & SSHMUX_FLAG_SUBSYS) != 0;
 688         cctx->term = buffer_get_string(&m, &len);
 689
 690         cmd = buffer_get_string(&m, &len);
 691         buffer_init(&cctx->cmd);
 692         buffer_append(&cctx->cmd, cmd, strlen(cmd));
 693
 694         env_len = buffer_get_int(&m);
 695         env_len = MIN(env_len, 4096);
 696         debug3("%s: receiving %d env vars", __func__, env_len);
 697         if (env_len != 0) {
 698                 cctx->env = xmalloc(sizeof(*cctx->env) * (env_len + 1));
 699                 for (i = 0; i < env_len; i++)
 700                         cctx->env[i] = buffer_get_string(&m, &len);
 701                 cctx->env[i] = NULL;
 702         }
 703
 704         debug2("%s: accepted tty %d, subsys %d, cmd %s", __func__,
 705             cctx->want_tty, cctx->want_subsys, cmd);
 706
 707         /* Gather fds from client */
 708         new_fd[0] = mm_receive_fd(client_fd);
 709         new_fd[1] = mm_receive_fd(client_fd);
 710         new_fd[2] = mm_receive_fd(client_fd);
 711
 712         debug2("%s: got fds stdin %d, stdout %d, stderr %d", __func__,
 713             new_fd[0], new_fd[1], new_fd[2]);
 714
 715         /* Try to pick up ttymodes from client before it goes raw */
 716         if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1)
 717                 error("%s: tcgetattr: %s", __func__, strerror(errno));
 718
 719         /* This roundtrip is just for synchronisation of ttymodes */
 720         buffer_clear(&m);
 721         if (ssh_msg_send(client_fd, /* version */1, &m) == -1) {
 722                 error("%s: client msg_send failed", __func__);
 723                 close(client_fd);
 724                 close(new_fd[0]);
 725                 close(new_fd[1]);
 726                 close(new_fd[2]);
 727                 buffer_free(&m);
 728                 xfree(cctx->term);
 729                 if (env_len != 0) {
 730                         for (i = 0; i < env_len; i++)
 731                                 xfree(cctx->env[i]);
 732                         xfree(cctx->env);
 733                 }
 734                 return;
 735         }
 736         buffer_free(&m);
 737
 738         /* enable nonblocking unless tty */
 739         if (!isatty(new_fd[0]))
 740                 set_nonblock(new_fd[0]);
 741         if (!isatty(new_fd[1]))
 742                 set_nonblock(new_fd[1]);
 743         if (!isatty(new_fd[2]))
 744                 set_nonblock(new_fd[2]);
 745
 746         set_nonblock(client_fd);
 747
 748         c = channel_new("session", SSH_CHANNEL_OPENING,
 749             new_fd[0], new_fd[1], new_fd[2],
 750             CHAN_SES_WINDOW_DEFAULT, CHAN_SES_PACKET_DEFAULT,
 751             CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0);
 752
 753         /* XXX */
 754         c->ctl_fd = client_fd;
 755
 756         debug3("%s: channel_new: %d", __func__, c->self);
 757
 758         channel_send_open(c->self);
 759         channel_register_confirm(c->self, client_extra_session2_setup, cctx);
 760 }
 761
 762 static void
 763 process_cmdline(void)
 764 {
 765         void (*handler)(int);
 766         char *s, *cmd;
 767         u_short fwd_port, fwd_host_port;
 768         char buf[1024], sfwd_port[6], sfwd_host_port[6];
 769         int delete = 0;
 770         int local = 0;
 771
 772         leave_raw_mode();
 773         handler = signal(SIGINT, SIG_IGN);
 774         cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
 775         if (s == NULL)
 776                 goto out;
 777         while (*s && isspace(*s))
 778                 s++;
 779         if (*s == '-')
 780                 s++;    /* Skip cmdline '-', if any */
 781         if (*s == '\0')
 782                 goto out;
 783
 784         if (*s == 'h' || *s == 'H' || *s == '?') {
 785                 logit("Commands:");
 786                 logit("      -Lport:host:hostport    Request local forward");
 787                 logit("      -Rport:host:hostport    Request remote forward");
 788                 logit("      -KRhostport             Cancel remote forward");
 789                 goto out;
 790         }
 791
 792         if (*s == 'K') {
 793                 delete = 1;
 794                 s++;
 795         }
 796         if (*s != 'L' && *s != 'R') {
 797                 logit("Invalid command.");
 798                 goto out;
 799         }
 800         if (*s == 'L')
 801                 local = 1;
 802         if (local && delete) {
 803                 logit("Not supported.");
 804                 goto out;
 805         }
 806         if ((!local || delete) && !compat20) {
 807                 logit("Not supported for SSH protocol version 1.");
 808                 goto out;
 809         }
 810
 811         s++;
 812         while (*s && isspace(*s))
 813                 s++;
 814
 815         if (delete) {
 816                 if (sscanf(s, "%5[0-9]", sfwd_host_port) != 1) {
 817                         logit("Bad forwarding specification.");
 818                         goto out;
 819                 }
 820                 if ((fwd_host_port = a2port(sfwd_host_port)) == 0) {
 821                         logit("Bad forwarding port(s).");
 822                         goto out;
 823                 }
 824                 channel_request_rforward_cancel(fwd_host_port);
 825         } else {
 826                 if (sscanf(s, "%5[0-9]:%255[^:]:%5[0-9]",
 827                     sfwd_port, buf, sfwd_host_port) != 3 &&
 828                     sscanf(s, "%5[0-9]/%255[^/]/%5[0-9]",
 829                     sfwd_port, buf, sfwd_host_port) != 3) {
 830                         logit("Bad forwarding specification.");
 831                         goto out;
 832                 }
 833                 if ((fwd_port = a2port(sfwd_port)) == 0 ||
 834                     (fwd_host_port = a2port(sfwd_host_port)) == 0) {
 835                         logit("Bad forwarding port(s).");
 836                         goto out;
 837                 }
 838                 if (local) {
 839                         if (channel_setup_local_fwd_listener(fwd_port, buf,
 840                             fwd_host_port, options.gateway_ports) < 0) {
 841                                 logit("Port forwarding failed.");
 842                                 goto out;
 843                         }
 844                 } else
 845                         channel_request_remote_forwarding(fwd_port, buf,
 846                             fwd_host_port);
 847                 logit("Forwarding port.");
 848         }
 849
 850 out:
 851         signal(SIGINT, handler);
 852         enter_raw_mode();
 853         if (cmd)
 854                 xfree(cmd);
 855 }
 856
 857 /* process the characters one by one */
 858 static int
 859 process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
 860 {
 861         char string[1024];
 862         pid_t pid;
 863         int bytes = 0;
 864         u_int i;
 865         u_char ch;
 866         char *s;
 867
 868         for (i = 0; i < len; i++) {
 869                 /* Get one character at a time. */
 870                 ch = buf[i];
 871
 872                 if (escape_pending) {
 873                         /* We have previously seen an escape character. */
 874                         /* Clear the flag now. */
 875                         escape_pending = 0;
 876
 877                         /* Process the escaped character. */
 878                         switch (ch) {
 879                         case '.':
 880                                 /* Terminate the connection. */
 881                                 snprintf(string, sizeof string, "%c.\r\n", escape_char);
 882                                 buffer_append(berr, string, strlen(string));
 883
 884                                 quit_pending = 1;
 885                                 return -1;
 886
 887                         case 'Z' - 64:
 888                                 /* Suspend the program. */
 889                                 /* Print a message to that effect to the user. */
 890                                 snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char);
 891                                 buffer_append(berr, string, strlen(string));
 892
 893                                 /* Restore terminal modes and suspend. */
 894                                 client_suspend_self(bin, bout, berr);
 895
 896                                 /* We have been continued. */
 897                                 continue;
 898
 899                         case 'B':
 900                                 if (compat20) {
 901                                         snprintf(string, sizeof string,
 902                                             "%cB\r\n", escape_char);
 903                                         buffer_append(berr, string,
 904                                             strlen(string));
 905                                         channel_request_start(session_ident,
 906                                             "break", 0);
 907                                         packet_put_int(1000);
 908                                         packet_send();
 909                                 }
 910                                 continue;
 911
 912                         case 'R':
 913                                 if (compat20) {
 914                                         if (datafellows & SSH_BUG_NOREKEY)
 915                                                 logit("Server does not support re-keying");
 916                                         else
 917                                                 need_rekeying = 1;
 918                                 }
 919                                 continue;
 920
 921                         case '&':
 922                                 /*
 923                                  * Detach the program (continue to serve connections,
 924                                  * but put in background and no more new connections).
 925                                  */
 926                                 /* Restore tty modes. */
 927                                 leave_raw_mode();
 928
 929                                 /* Stop listening for new connections. */
 930                                 channel_stop_listening();
 931
 932                                 snprintf(string, sizeof string,
 933                                     "%c& [backgrounded]\n", escape_char);
 934                                 buffer_append(berr, string, strlen(string));
 935
 936                                 /* Fork into background. */
 937                                 pid = fork();
 938                                 if (pid < 0) {
 939                                         error("fork: %.100s", strerror(errno));
 940                                         continue;
 941                                 }
 942                                 if (pid != 0) { /* This is the parent. */
 943                                         /* The parent just exits. */
 944                                         exit(0);
 945                                 }
 946                                 /* The child continues serving connections. */
 947                                 if (compat20) {
 948                                         buffer_append(bin, "\004", 1);
 949                                         /* fake EOF on stdin */
 950                                         return -1;
 951                                 } else if (!stdin_eof) {
 952                                         /*
 953                                          * Sending SSH_CMSG_EOF alone does not always appear
 954                                          * to be enough.  So we try to send an EOF character
 955                                          * first.
 956                                          */
 957                                         packet_start(SSH_CMSG_STDIN_DATA);
 958                                         packet_put_string("\004", 1);
 959                                         packet_send();
 960                                         /* Close stdin. */
 961                                         stdin_eof = 1;
 962                                         if (buffer_len(bin) == 0) {
 963                                                 packet_start(SSH_CMSG_EOF);
 964                                                 packet_send();
 965                                         }
 966                                 }
 967                                 continue;
 968
 969                         case '?':
 970                                 snprintf(string, sizeof string,
 971 "%c?\r\n\
 972 Supported escape sequences:\r\n\
 973 %c.  - terminate connection\r\n\
 974 %cB  - send a BREAK to the remote system\r\n\
 975 %cC  - open a command line\r\n\
 976 %cR  - Request rekey (SSH protocol 2 only)\r\n\
 977 %c^Z - suspend ssh\r\n\
 978 %c#  - list forwarded connections\r\n\
 979 %c&  - background ssh (when waiting for connections to terminate)\r\n\
 980 %c?  - this message\r\n\
 981 %c%c  - send the escape character by typing it twice\r\n\
 982 (Note that escapes are only recognized immediately after newline.)\r\n",
 983                                     escape_char, escape_char, escape_char, escape_char,
 984                                     escape_char, escape_char, escape_char, escape_char,
 985                                     escape_char, escape_char, escape_char);
 986                                 buffer_append(berr, string, strlen(string));
 987                                 continue;
 988
 989                         case '#':
 990                                 snprintf(string, sizeof string, "%c#\r\n", escape_char);
 991                                 buffer_append(berr, string, strlen(string));
 992                                 s = channel_open_message();
 993                                 buffer_append(berr, s, strlen(s));
 994                                 xfree(s);
 995                                 continue;
 996
 997                         case 'C':
 998                                 process_cmdline();
 999                                 continue;
1000
1001                         default:
1002                                 if (ch != escape_char) {
1003                                         buffer_put_char(bin, escape_char);
1004                                         bytes++;
1005                                 }
1006                                 /* Escaped characters fall through here */
1007                                 break;
1008                         }
1009                 } else {
1010                         /*
1011                          * The previous character was not an escape char. Check if this
1012                          * is an escape.
1013                          */
1014                         if (last_was_cr && ch == escape_char) {
1015                                 /* It is. Set the flag and continue to next character. */
1016                                 escape_pending = 1;
1017                                 continue;
1018                         }
1019                 }
1020
1021                 /*
1022                  * Normal character.  Record whether it was a newline,
1023                  * and append it to the buffer.
1024                  */
1025                 last_was_cr = (ch == '\r' || ch == '\n');
1026                 buffer_put_char(bin, ch);
1027                 bytes++;
1028         }
1029         return bytes;
1030 }
1031
1032 static void
1033 client_process_input(fd_set * readset)
1034 {
1035         int len;
1036         char buf[8192];
1037
1038         /* Read input from stdin. */
1039         if (FD_ISSET(fileno(stdin), readset)) {
1040                 /* Read as much as possible. */
1041                 len = read(fileno(stdin), buf, sizeof(buf));
1042                 if (len < 0 && (errno == EAGAIN || errno == EINTR))
1043                         return;         /* we'll try again later */
1044                 if (len <= 0) {
1045                         /*
1046                          * Received EOF or error.  They are treated
1047                          * similarly, except that an error message is printed
1048                          * if it was an error condition.
1049                          */
1050                         if (len < 0) {
1051                                 snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno));
1052                                 buffer_append(&stderr_buffer, buf, strlen(buf));
1053                         }
1054                         /* Mark that we have seen EOF. */
1055                         stdin_eof = 1;
1056                         /*
1057                          * Send an EOF message to the server unless there is
1058                          * data in the buffer.  If there is data in the
1059                          * buffer, no message will be sent now.  Code
1060                          * elsewhere will send the EOF when the buffer
1061                          * becomes empty if stdin_eof is set.
1062                          */
1063                         if (buffer_len(&stdin_buffer) == 0) {
1064                                 packet_start(SSH_CMSG_EOF);
1065                                 packet_send();
1066                         }
1067                 } else if (escape_char == SSH_ESCAPECHAR_NONE) {
1068                         /*
1069                          * Normal successful read, and no escape character.
1070                          * Just append the data to buffer.
1071                          */
1072                         buffer_append(&stdin_buffer, buf, len);
1073                 } else {
1074                         /*
1075                          * Normal, successful read.  But we have an escape character
1076                          * and have to process the characters one by one.
1077                          */
1078                         if (process_escapes(&stdin_buffer, &stdout_buffer,
1079                             &stderr_buffer, buf, len) == -1)
1080                                 return;
1081                 }
1082         }
1083 }
1084
1085 static void
1086 client_process_output(fd_set * writeset)
1087 {
1088         int len;
1089         char buf[100];
1090
1091         /* Write buffered output to stdout. */
1092         if (FD_ISSET(fileno(stdout), writeset)) {
1093                 /* Write as much data as possible. */
1094                 len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1095                     buffer_len(&stdout_buffer));
1096                 if (len <= 0) {
1097                         if (errno == EINTR || errno == EAGAIN)
1098                                 len = 0;
1099                         else {
1100                                 /*
1101                                  * An error or EOF was encountered.  Put an
1102                                  * error message to stderr buffer.
1103                                  */
1104                                 snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno));
1105                                 buffer_append(&stderr_buffer, buf, strlen(buf));
1106                                 quit_pending = 1;
1107                                 return;
1108                         }
1109                 }
1110                 /* Consume printed data from the buffer. */
1111                 buffer_consume(&stdout_buffer, len);
1112                 stdout_bytes += len;
1113         }
1114         /* Write buffered output to stderr. */
1115         if (FD_ISSET(fileno(stderr), writeset)) {
1116                 /* Write as much data as possible. */
1117                 len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1118                     buffer_len(&stderr_buffer));
1119                 if (len <= 0) {
1120                         if (errno == EINTR || errno == EAGAIN)
1121                                 len = 0;
1122                         else {
1123                                 /* EOF or error, but can't even print error message. */
1124                                 quit_pending = 1;
1125                                 return;
1126                         }
1127                 }
1128                 /* Consume printed characters from the buffer. */
1129                 buffer_consume(&stderr_buffer, len);
1130                 stderr_bytes += len;
1131         }
1132 }
1133
1134 /*
1135  * Get packets from the connection input buffer, and process them as long as
1136  * there are packets available.
1137  *
1138  * Any unknown packets received during the actual
1139  * session cause the session to terminate.  This is
1140  * intended to make debugging easier since no
1141  * confirmations are sent.  Any compatible protocol
1142  * extensions must be negotiated during the
1143  * preparatory phase.
1144  */
1145
1146 static void
1147 client_process_buffered_input_packets(void)
1148 {
1149         dispatch_run(DISPATCH_NONBLOCK, &quit_pending, compat20 ? xxx_kex : NULL);
1150 }
1151
1152 /* scan buf[] for '~' before sending data to the peer */
1153
1154 static int
1155 simple_escape_filter(Channel *c, char *buf, int len)
1156 {
1157         /* XXX we assume c->extended is writeable */
1158         return process_escapes(&c->input, &c->output, &c->extended, buf, len);
1159 }
1160
1161 static void
1162 client_channel_closed(int id, void *arg)
1163 {
1164         channel_cancel_cleanup(id);
1165         session_closed = 1;
1166         leave_raw_mode();
1167 }
1168
1169 /*
1170  * Implements the interactive session with the server.  This is called after
1171  * the user has been authenticated, and a command has been started on the
1172  * remote host.  If escape_char != SSH_ESCAPECHAR_NONE, it is the character
1173  * used as an escape character for terminating or suspending the session.
1174  */
1175
1176 int
1177 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
1178 {
1179         fd_set *readset = NULL, *writeset = NULL;
1180         double start_time, total_time;
1181         int max_fd = 0, max_fd2 = 0, len, rekeying = 0;
1182         u_int nalloc = 0;
1183         char buf[100];
1184
1185         debug("Entering interactive session.");
1186
1187         start_time = get_current_time();
1188
1189         /* Initialize variables. */
1190         escape_pending = 0;
1191         last_was_cr = 1;
1192         exit_status = -1;
1193         stdin_eof = 0;
1194         buffer_high = 64 * 1024;
1195         connection_in = packet_get_connection_in();
1196         connection_out = packet_get_connection_out();
1197         max_fd = MAX(connection_in, connection_out);
1198         if (control_fd != -1)
1199                 max_fd = MAX(max_fd, control_fd);
1200
1201         if (!compat20) {
1202                 /* enable nonblocking unless tty */
1203                 if (!isatty(fileno(stdin)))
1204                         set_nonblock(fileno(stdin));
1205                 if (!isatty(fileno(stdout)))
1206                         set_nonblock(fileno(stdout));
1207                 if (!isatty(fileno(stderr)))
1208                         set_nonblock(fileno(stderr));
1209                 max_fd = MAX(max_fd, fileno(stdin));
1210                 max_fd = MAX(max_fd, fileno(stdout));
1211                 max_fd = MAX(max_fd, fileno(stderr));
1212         }
1213         stdin_bytes = 0;
1214         stdout_bytes = 0;
1215         stderr_bytes = 0;
1216         quit_pending = 0;
1217         escape_char = escape_char_arg;
1218
1219         /* Initialize buffers. */
1220         buffer_init(&stdin_buffer);
1221         buffer_init(&stdout_buffer);
1222         buffer_init(&stderr_buffer);
1223
1224         client_init_dispatch();
1225
1226         /*
1227          * Set signal handlers, (e.g. to restore non-blocking mode)
1228          * but don't overwrite SIG_IGN, matches behaviour from rsh(1)
1229          */
1230         if (signal(SIGHUP, SIG_IGN) != SIG_IGN)
1231                 signal(SIGHUP, signal_handler);
1232         if (signal(SIGINT, SIG_IGN) != SIG_IGN)
1233                 signal(SIGINT, signal_handler);
1234         if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
1235                 signal(SIGQUIT, signal_handler);
1236         if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
1237                 signal(SIGTERM, signal_handler);
1238         signal(SIGWINCH, window_change_handler);
1239
1240         if (have_pty)
1241                 enter_raw_mode();
1242
1243         if (compat20) {
1244                 session_ident = ssh2_chan_id;
1245                 if (escape_char != SSH_ESCAPECHAR_NONE)
1246                         channel_register_filter(session_ident,
1247                             simple_escape_filter);
1248                 if (session_ident != -1)
1249                         channel_register_cleanup(session_ident,
1250                             client_channel_closed);
1251         } else {
1252                 /* Check if we should immediately send eof on stdin. */
1253                 client_check_initial_eof_on_stdin();
1254         }
1255
1256         /* Main loop of the client for the interactive session mode. */
1257         while (!quit_pending) {
1258
1259                 /* Process buffered packets sent by the server. */
1260                 client_process_buffered_input_packets();
1261
1262                 if (compat20 && session_closed && !channel_still_open())
1263                         break;
1264
1265                 rekeying = (xxx_kex != NULL && !xxx_kex->done);
1266
1267                 if (rekeying) {
1268                         debug("rekeying in progress");
1269                 } else {
1270                         /*
1271                          * Make packets of buffered stdin data, and buffer
1272                          * them for sending to the server.
1273                          */
1274                         if (!compat20)
1275                                 client_make_packets_from_stdin_data();
1276
1277                         /*
1278                          * Make packets from buffered channel data, and
1279                          * enqueue them for sending to the server.
1280                          */
1281                         if (packet_not_very_much_data_to_write())
1282                                 channel_output_poll();
1283
1284                         /*
1285                          * Check if the window size has changed, and buffer a
1286                          * message about it to the server if so.
1287                          */
1288                         client_check_window_change();
1289
1290                         if (quit_pending)
1291                                 break;
1292                 }
1293                 /*
1294                  * Wait until we have something to do (something becomes
1295                  * available on one of the descriptors).
1296                  */
1297                 max_fd2 = max_fd;
1298                 client_wait_until_can_do_something(&readset, &writeset,
1299                     &max_fd2, &nalloc, rekeying);
1300
1301                 if (quit_pending)
1302                         break;
1303
1304                 /* Do channel operations unless rekeying in progress. */
1305                 if (!rekeying) {
1306                         channel_after_select(readset, writeset);
1307                         if (need_rekeying || packet_need_rekeying()) {
1308                                 debug("need rekeying");
1309                                 xxx_kex->done = 0;
1310                                 kex_send_kexinit(xxx_kex);
1311                                 need_rekeying = 0;
1312                         }
1313                 }
1314
1315                 /* Buffer input from the connection.  */
1316                 client_process_net_input(readset);
1317
1318                 /* Accept control connections.  */
1319                 client_process_control(readset);
1320
1321                 if (quit_pending)
1322                         break;
1323
1324                 if (!compat20) {
1325                         /* Buffer data from stdin */
1326                         client_process_input(readset);
1327                         /*
1328                          * Process output to stdout and stderr.  Output to
1329                          * the connection is processed elsewhere (above).
1330                          */
1331                         client_process_output(writeset);
1332                 }
1333
1334                 /* Send as much buffered packet data as possible to the sender. */
1335                 if (FD_ISSET(connection_out, writeset))
1336                         packet_write_poll();
1337         }
1338         if (readset)
1339                 xfree(readset);
1340         if (writeset)
1341                 xfree(writeset);
1342
1343         /* Terminate the session. */
1344
1345         /* Stop watching for window change. */
1346         signal(SIGWINCH, SIG_DFL);
1347
1348         channel_free_all();
1349
1350         if (have_pty)
1351                 leave_raw_mode();
1352
1353         /* restore blocking io */
1354         if (!isatty(fileno(stdin)))
1355                 unset_nonblock(fileno(stdin));
1356         if (!isatty(fileno(stdout)))
1357                 unset_nonblock(fileno(stdout));
1358         if (!isatty(fileno(stderr)))
1359                 unset_nonblock(fileno(stderr));
1360
1361         /*
1362          * If there was no shell or command requested, there will be no remote
1363          * exit status to be returned.  In that case, clear error code if the
1364          * connection was deliberately terminated at this end.
1365          */
1366         if (no_shell_flag && received_signal == SIGTERM) {
1367                 received_signal = 0;
1368                 exit_status = 0;
1369         }
1370
1371         if (received_signal)
1372                 fatal("Killed by signal %d.", (int) received_signal);
1373
1374         /*
1375          * In interactive mode (with pseudo tty) display a message indicating
1376          * that the connection has been closed.
1377          */
1378         if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
1379                 snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host);
1380                 buffer_append(&stderr_buffer, buf, strlen(buf));
1381         }
1382
1383         /* Output any buffered data for stdout. */
1384         while (buffer_len(&stdout_buffer) > 0) {
1385                 len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1386                     buffer_len(&stdout_buffer));
1387                 if (len <= 0) {
1388                         error("Write failed flushing stdout buffer.");
1389                         break;
1390                 }
1391                 buffer_consume(&stdout_buffer, len);
1392                 stdout_bytes += len;
1393         }
1394
1395         /* Output any buffered data for stderr. */
1396         while (buffer_len(&stderr_buffer) > 0) {
1397                 len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1398                     buffer_len(&stderr_buffer));
1399                 if (len <= 0) {
1400                         error("Write failed flushing stderr buffer.");
1401                         break;
1402                 }
1403                 buffer_consume(&stderr_buffer, len);
1404                 stderr_bytes += len;
1405         }
1406
1407         /* Clear and free any buffers. */
1408         memset(buf, 0, sizeof(buf));
1409         buffer_free(&stdin_buffer);
1410         buffer_free(&stdout_buffer);
1411         buffer_free(&stderr_buffer);
1412
1413         /* Report bytes transferred, and transfer rates. */
1414         total_time = get_current_time() - start_time;
1415         debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
1416             stdin_bytes, stdout_bytes, stderr_bytes, total_time);
1417         if (total_time > 0)
1418                 debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
1419                     stdin_bytes / total_time, stdout_bytes / total_time,
1420                     stderr_bytes / total_time);
1421
1422         /* Return the exit status of the program. */
1423         debug("Exit status %d", exit_status);
1424         return exit_status;
1425 }
1426
1427 /*********/
1428
1429 static void
1430 client_input_stdout_data(int type, u_int32_t seq, void *ctxt)
1431 {
1432         u_int data_len;
1433         char *data = packet_get_string(&data_len);
1434         packet_check_eom();
1435         buffer_append(&stdout_buffer, data, data_len);
1436         memset(data, 0, data_len);
1437         xfree(data);
1438 }
1439 static void
1440 client_input_stderr_data(int type, u_int32_t seq, void *ctxt)
1441 {
1442         u_int data_len;
1443         char *data = packet_get_string(&data_len);
1444         packet_check_eom();
1445         buffer_append(&stderr_buffer, data, data_len);
1446         memset(data, 0, data_len);
1447         xfree(data);
1448 }
1449 static void
1450 client_input_exit_status(int type, u_int32_t seq, void *ctxt)
1451 {
1452         exit_status = packet_get_int();
1453         packet_check_eom();
1454         /* Acknowledge the exit. */
1455         packet_start(SSH_CMSG_EXIT_CONFIRMATION);
1456         packet_send();
1457         /*
1458          * Must wait for packet to be sent since we are
1459          * exiting the loop.
1460          */
1461         packet_write_wait();
1462         /* Flag that we want to exit. */
1463         quit_pending = 1;
1464 }
1465 static void
1466 client_input_agent_open(int type, u_int32_t seq, void *ctxt)
1467 {
1468         Channel *c = NULL;
1469         int remote_id, sock;
1470
1471         /* Read the remote channel number from the message. */
1472         remote_id = packet_get_int();
1473         packet_check_eom();
1474
1475         /*
1476          * Get a connection to the local authentication agent (this may again
1477          * get forwarded).
1478          */
1479         sock = ssh_get_authentication_socket();
1480
1481         /*
1482          * If we could not connect the agent, send an error message back to
1483          * the server. This should never happen unless the agent dies,
1484          * because authentication forwarding is only enabled if we have an
1485          * agent.
1486          */
1487         if (sock >= 0) {
1488                 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
1489                     -1, 0, 0, 0, "authentication agent connection", 1);
1490                 c->remote_id = remote_id;
1491                 c->force_drain = 1;
1492         }
1493         if (c == NULL) {
1494                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1495                 packet_put_int(remote_id);
1496         } else {
1497                 /* Send a confirmation to the remote host. */
1498                 debug("Forwarding authentication connection.");
1499                 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1500                 packet_put_int(remote_id);
1501                 packet_put_int(c->self);
1502         }
1503         packet_send();
1504 }
1505
1506 static Channel *
1507 client_request_forwarded_tcpip(const char *request_type, int rchan)
1508 {
1509         Channel *c = NULL;
1510         char *listen_address, *originator_address;
1511         int listen_port, originator_port;
1512         int sock;
1513
1514         /* Get rest of the packet */
1515         listen_address = packet_get_string(NULL);
1516         listen_port = packet_get_int();
1517         originator_address = packet_get_string(NULL);
1518         originator_port = packet_get_int();
1519         packet_check_eom();
1520
1521         debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d",
1522             listen_address, listen_port, originator_address, originator_port);
1523
1524         sock = channel_connect_by_listen_address(listen_port);
1525         if (sock < 0) {
1526                 xfree(originator_address);
1527                 xfree(listen_address);
1528                 return NULL;
1529         }
1530         c = channel_new("forwarded-tcpip",
1531             SSH_CHANNEL_CONNECTING, sock, sock, -1,
1532             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
1533             originator_address, 1);
1534         xfree(originator_address);
1535         xfree(listen_address);
1536         return c;
1537 }
1538
1539 static Channel *
1540 client_request_x11(const char *request_type, int rchan)
1541 {
1542         Channel *c = NULL;
1543         char *originator;
1544         int originator_port;
1545         int sock;
1546
1547         if (!options.forward_x11) {
1548                 error("Warning: ssh server tried X11 forwarding.");
1549                 error("Warning: this is probably a break in attempt by a malicious server.");
1550                 return NULL;
1551         }
1552         originator = packet_get_string(NULL);
1553         if (datafellows & SSH_BUG_X11FWD) {
1554                 debug2("buggy server: x11 request w/o originator_port");
1555                 originator_port = 0;
1556         } else {
1557                 originator_port = packet_get_int();
1558         }
1559         packet_check_eom();
1560         /* XXX check permission */
1561         debug("client_request_x11: request from %s %d", originator,
1562             originator_port);
1563         xfree(originator);
1564         sock = x11_connect_display();
1565         if (sock < 0)
1566                 return NULL;
1567         c = channel_new("x11",
1568             SSH_CHANNEL_X11_OPEN, sock, sock, -1,
1569             CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1);
1570         c->force_drain = 1;
1571         return c;
1572 }
1573
1574 static Channel *
1575 client_request_agent(const char *request_type, int rchan)
1576 {
1577         Channel *c = NULL;
1578         int sock;
1579
1580         if (!options.forward_agent) {
1581                 error("Warning: ssh server tried agent forwarding.");
1582                 error("Warning: this is probably a break in attempt by a malicious server.");
1583                 return NULL;
1584         }
1585         sock =  ssh_get_authentication_socket();
1586         if (sock < 0)
1587                 return NULL;
1588         c = channel_new("authentication agent connection",
1589             SSH_CHANNEL_OPEN, sock, sock, -1,
1590             CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
1591             "authentication agent connection", 1);
1592         c->force_drain = 1;
1593         return c;
1594 }
1595
1596 /* XXXX move to generic input handler */
1597 static void
1598 client_input_channel_open(int type, u_int32_t seq, void *ctxt)
1599 {
1600         Channel *c = NULL;
1601         char *ctype;
1602         int rchan;
1603         u_int rmaxpack, rwindow, len;
1604
1605         ctype = packet_get_string(&len);
1606         rchan = packet_get_int();
1607         rwindow = packet_get_int();
1608         rmaxpack = packet_get_int();
1609
1610         debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
1611             ctype, rchan, rwindow, rmaxpack);
1612
1613         if (strcmp(ctype, "forwarded-tcpip") == 0) {
1614                 c = client_request_forwarded_tcpip(ctype, rchan);
1615         } else if (strcmp(ctype, "x11") == 0) {
1616                 c = client_request_x11(ctype, rchan);
1617         } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) {
1618                 c = client_request_agent(ctype, rchan);
1619         }
1620 /* XXX duplicate : */
1621         if (c != NULL) {
1622                 debug("confirm %s", ctype);
1623                 c->remote_id = rchan;
1624                 c->remote_window = rwindow;
1625                 c->remote_maxpacket = rmaxpack;
1626                 if (c->type != SSH_CHANNEL_CONNECTING) {
1627                         packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1628                         packet_put_int(c->remote_id);
1629                         packet_put_int(c->self);
1630                         packet_put_int(c->local_window);
1631                         packet_put_int(c->local_maxpacket);
1632                         packet_send();
1633                 }
1634         } else {
1635                 debug("failure %s", ctype);
1636                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1637                 packet_put_int(rchan);
1638                 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1639                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1640                         packet_put_cstring("open failed");
1641                         packet_put_cstring("");
1642                 }
1643                 packet_send();
1644         }
1645         xfree(ctype);
1646 }
1647 static void
1648 client_input_channel_req(int type, u_int32_t seq, void *ctxt)
1649 {
1650         Channel *c = NULL;
1651         int exitval, id, reply, success = 0;
1652         char *rtype;
1653
1654         id = packet_get_int();
1655         rtype = packet_get_string(NULL);
1656         reply = packet_get_char();
1657
1658         debug("client_input_channel_req: channel %d rtype %s reply %d",
1659             id, rtype, reply);
1660
1661         if (id == -1) {
1662                 error("client_input_channel_req: request for channel -1");
1663         } else if ((c = channel_lookup(id)) == NULL) {
1664                 error("client_input_channel_req: channel %d: unknown channel", id);
1665         } else if (strcmp(rtype, "exit-status") == 0) {
1666                 exitval = packet_get_int();
1667                 if (id == session_ident) {
1668                         success = 1;
1669                         exit_status = exitval;
1670                 } else if (c->ctl_fd == -1) {
1671                         error("client_input_channel_req: unexpected channel %d",
1672                             session_ident);
1673                 } else {
1674                         atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval));
1675                         success = 1;
1676                 }
1677                 packet_check_eom();
1678         }
1679         if (reply) {
1680                 packet_start(success ?
1681                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1682                 packet_put_int(id);
1683                 packet_send();
1684         }
1685         xfree(rtype);
1686 }
1687 static void
1688 client_input_global_request(int type, u_int32_t seq, void *ctxt)
1689 {
1690         char *rtype;
1691         int want_reply;
1692         int success = 0;
1693
1694         rtype = packet_get_string(NULL);
1695         want_reply = packet_get_char();
1696         debug("client_input_global_request: rtype %s want_reply %d",
1697             rtype, want_reply);
1698         if (want_reply) {
1699                 packet_start(success ?
1700                     SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1701                 packet_send();
1702                 packet_write_wait();
1703         }
1704         xfree(rtype);
1705 }
1706
1707 void
1708 client_session2_setup(int id, int want_tty, int want_subsystem,
1709     const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env,
1710     dispatch_fn *subsys_repl)
1711 {
1712         int len;
1713         Channel *c = NULL;
1714
1715         debug2("%s: id %d", __func__, id);
1716
1717         if ((c = channel_lookup(id)) == NULL)
1718                 fatal("client_session2_setup: channel %d: unknown channel", id);
1719
1720         if (want_tty) {
1721                 struct winsize ws;
1722                 struct termios tio;
1723
1724                 /* Store window size in the packet. */
1725                 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0)
1726                         memset(&ws, 0, sizeof(ws));
1727
1728                 channel_request_start(id, "pty-req", 0);
1729                 packet_put_cstring(term != NULL ? term : "");
1730                 packet_put_int(ws.ws_col);
1731                 packet_put_int(ws.ws_row);
1732                 packet_put_int(ws.ws_xpixel);
1733                 packet_put_int(ws.ws_ypixel);
1734                 tio = get_saved_tio();
1735                 tty_make_modes(-1, tiop != NULL ? tiop : &tio);
1736                 packet_send();
1737                 /* XXX wait for reply */
1738                 c->client_tty = 1;
1739         }
1740
1741         /* Transfer any environment variables from client to server */
1742         if (options.num_send_env != 0 && env != NULL) {
1743                 int i, j, matched;
1744                 char *name, *val;
1745
1746                 debug("Sending environment.");
1747                 for (i = 0; env[i] != NULL; i++) {
1748                         /* Split */
1749                         name = xstrdup(env[i]);
1750                         if ((val = strchr(name, '=')) == NULL) {
1751                                 free(name);
1752                                 continue;
1753                         }
1754                         *val++ = '\0';
1755
1756                         matched = 0;
1757                         for (j = 0; j < options.num_send_env; j++) {
1758                                 if (match_pattern(name, options.send_env[j])) {
1759                                         matched = 1;
1760                                         break;
1761                                 }
1762                         }
1763                         if (!matched) {
1764                                 debug3("Ignored env %s", name);
1765                                 free(name);
1766                                 continue;
1767                         }
1768
1769                         debug("Sending env %s = %s", name, val);
1770                         channel_request_start(id, "env", 0);
1771                         packet_put_cstring(name);
1772                         packet_put_cstring(val);
1773                         packet_send();
1774                         free(name);
1775                 }
1776         }
1777
1778         len = buffer_len(cmd);
1779         if (len > 0) {
1780                 if (len > 900)
1781                         len = 900;
1782                 if (want_subsystem) {
1783                         debug("Sending subsystem: %.*s", len, (u_char*)buffer_ptr(cmd));
1784                         channel_request_start(id, "subsystem", subsys_repl != NULL);
1785                         if (subsys_repl != NULL) {
1786                                 /* register callback for reply */
1787                                 /* XXX we assume that client_loop has already been called */
1788                                 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, subsys_repl);
1789                                 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, subsys_repl);
1790                         }
1791                 } else {
1792                         debug("Sending command: %.*s", len, (u_char*)buffer_ptr(cmd));
1793                         channel_request_start(id, "exec", 0);
1794                 }
1795                 packet_put_string(buffer_ptr(cmd), buffer_len(cmd));
1796                 packet_send();
1797         } else {
1798                 channel_request_start(id, "shell", 0);
1799                 packet_send();
1800         }
1801 }
1802
1803 static void
1804 client_init_dispatch_20(void)
1805 {
1806         dispatch_init(&dispatch_protocol_error);
1807
1808         dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1809         dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1810         dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1811         dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1812         dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
1813         dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1814         dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1815         dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
1816         dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1817         dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);
1818
1819         /* rekeying */
1820         dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1821
1822         /* global request reply messages */
1823         dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
1824         dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
1825 }
1826 static void
1827 client_init_dispatch_13(void)
1828 {
1829         dispatch_init(NULL);
1830         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1831         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1832         dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1833         dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1834         dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1835         dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1836         dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
1837         dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
1838         dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);
1839
1840         dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ?
1841             &client_input_agent_open : &deny_input_open);
1842         dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ?
1843             &x11_input_open : &deny_input_open);
1844 }
1845 static void
1846 client_init_dispatch_15(void)
1847 {
1848         client_init_dispatch_13();
1849         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1850         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
1851 }
1852 static void
1853 client_init_dispatch(void)
1854 {
1855         if (compat20)
1856                 client_init_dispatch_20();
1857         else if (compat13)
1858                 client_init_dispatch_13();
1859         else
1860                 client_init_dispatch_15();
1861 }
1862
1863 /* client specific fatal cleanup */
1864 void
1865 cleanup_exit(int i)
1866 {
1867         leave_raw_mode();
1868         leave_non_blocking();
1869         if (options.control_path != NULL && control_fd != -1)
1870                 unlink(options.control_path);
1871         _exit(i);
1872 }