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 1.126 2004/06/17 14:52:48 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, 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         struct winsize oldws, newws;
 436
 437         /* Flush stdout and stderr buffers. */
 438         if (buffer_len(bout) > 0)
 439                 atomicio(vwrite, fileno(stdout), buffer_ptr(bout), buffer_len(bout));
 440         if (buffer_len(berr) > 0)
 441                 atomicio(vwrite, fileno(stderr), buffer_ptr(berr), buffer_len(berr));
 442
 443         leave_raw_mode();
 444
 445         /*
 446          * Free (and clear) the buffer to reduce the amount of data that gets
 447          * written to swap.
 448          */
 449         buffer_free(bin);
 450         buffer_free(bout);
 451         buffer_free(berr);
 452
 453         /* Save old window size. */
 454         ioctl(fileno(stdin), TIOCGWINSZ, &oldws);
 455
 456         /* Send the suspend signal to the program itself. */
 457         kill(getpid(), SIGTSTP);
 458
 459         /* Check if the window size has changed. */
 460         if (ioctl(fileno(stdin), TIOCGWINSZ, &newws) >= 0 &&
 461             (oldws.ws_row != newws.ws_row ||
 462             oldws.ws_col != newws.ws_col ||
 463             oldws.ws_xpixel != newws.ws_xpixel ||
 464             oldws.ws_ypixel != newws.ws_ypixel))
 465                 received_window_change_signal = 1;
 466
 467         /* OK, we have been continued by the user. Reinitialize buffers. */
 468         buffer_init(bin);
 469         buffer_init(bout);
 470         buffer_init(berr);
 471
 472         enter_raw_mode();
 473 }
 474
 475 static void
 476 client_process_net_input(fd_set * readset)
 477 {
 478         int len;
 479         char buf[8192];
 480
 481         /*
 482          * Read input from the server, and add any such data to the buffer of
 483          * the packet subsystem.
 484          */
 485         if (FD_ISSET(connection_in, readset)) {
 486                 /* Read as much as possible. */
 487                 len = read(connection_in, buf, sizeof(buf));
 488                 if (len == 0) {
 489                         /* Received EOF.  The remote host has closed the connection. */
 490                         snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n",
 491                                  host);
 492                         buffer_append(&stderr_buffer, buf, strlen(buf));
 493                         quit_pending = 1;
 494                         return;
 495                 }
 496                 /*
 497                  * There is a kernel bug on Solaris that causes select to
 498                  * sometimes wake up even though there is no data available.
 499                  */
 500                 if (len < 0 && (errno == EAGAIN || errno == EINTR))
 501                         len = 0;
 502
 503                 if (len < 0) {
 504                         /* An error has encountered.  Perhaps there is a network problem. */
 505                         snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n",
 506                                  host, strerror(errno));
 507                         buffer_append(&stderr_buffer, buf, strlen(buf));
 508                         quit_pending = 1;
 509                         return;
 510                 }
 511                 packet_process_incoming(buf, len);
 512         }
 513 }
 514
 515 static void
 516 client_subsystem_reply(int type, u_int32_t seq, void *ctxt)
 517 {
 518         int id;
 519         Channel *c;
 520
 521         id = packet_get_int();
 522         packet_check_eom();
 523
 524         if ((c = channel_lookup(id)) == NULL) {
 525                 error("%s: no channel for id %d", __func__, id);
 526                 return;
 527         }
 528
 529         if (type == SSH2_MSG_CHANNEL_SUCCESS)
 530                 debug2("Request suceeded on channel %d", id);
 531         else if (type == SSH2_MSG_CHANNEL_FAILURE) {
 532                 error("Request failed on channel %d", id);
 533                 channel_free(c);
 534         }
 535 }
 536
 537 static void
 538 client_extra_session2_setup(int id, void *arg)
 539 {
 540         struct confirm_ctx *cctx = arg;
 541         Channel *c;
 542         int i;
 543
 544         if (cctx == NULL)
 545                 fatal("%s: cctx == NULL", __func__);
 546         if ((c = channel_lookup(id)) == NULL)
 547                 fatal("%s: no channel for id %d", __func__, id);
 548
 549         client_session2_setup(id, cctx->want_tty, cctx->want_subsys,
 550             cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env,
 551             client_subsystem_reply);
 552
 553         c->confirm_ctx = NULL;
 554         buffer_free(&cctx->cmd);
 555         xfree(cctx->term);
 556         if (cctx->env != NULL) {
 557                 for (i = 0; cctx->env[i] != NULL; i++)
 558                         xfree(cctx->env[i]);
 559                 xfree(cctx->env);
 560         }
 561         xfree(cctx);
 562 }
 563
 564 static void
 565 client_process_control(fd_set * readset)
 566 {
 567         Buffer m;
 568         Channel *c;
 569         int client_fd, new_fd[3], ver, i;
 570         socklen_t addrlen;
 571         struct sockaddr_storage addr;
 572         struct confirm_ctx *cctx;
 573         char *cmd;
 574         u_int len, env_len;
 575         uid_t euid;
 576         gid_t egid;
 577
 578         /*
 579          * Accept connection on control socket
 580          */
 581         if (control_fd == -1 || !FD_ISSET(control_fd, readset))
 582                 return;
 583
 584         memset(&addr, 0, sizeof(addr));
 585         addrlen = sizeof(addr);
 586         if ((client_fd = accept(control_fd,
 587             (struct sockaddr*)&addr, &addrlen)) == -1) {
 588                 error("%s accept: %s", __func__, strerror(errno));
 589                 return;
 590         }
 591
 592         if (getpeereid(client_fd, &euid, &egid) < 0) {
 593                 error("%s getpeereid failed: %s", __func__, strerror(errno));
 594                 close(client_fd);
 595                 return;
 596         }
 597         if ((euid != 0) && (getuid() != euid)) {
 598                 error("control mode uid mismatch: peer euid %u != uid %u",
 599                     (u_int) euid, (u_int) getuid());
 600                 close(client_fd);
 601                 return;
 602         }
 603         /* XXX: implement use of ssh-askpass to confirm additional channels */
 604
 605         unset_nonblock(client_fd);
 606
 607         buffer_init(&m);
 608
 609         buffer_put_int(&m, getpid());
 610         if (ssh_msg_send(client_fd, /* version */0, &m) == -1) {
 611                 error("%s: client msg_send failed", __func__);
 612                 close(client_fd);
 613                 return;
 614         }
 615         buffer_clear(&m);
 616
 617         if (ssh_msg_recv(client_fd, &m) == -1) {
 618                 error("%s: client msg_recv failed", __func__);
 619                 close(client_fd);
 620                 return;
 621         }
 622
 623         if ((ver = buffer_get_char(&m)) != 0) {
 624                 error("%s: wrong client version %d", __func__, ver);
 625                 buffer_free(&m);
 626                 close(client_fd);
 627                 return;
 628         }
 629
 630         cctx = xmalloc(sizeof(*cctx));
 631         memset(cctx, 0, sizeof(*cctx));
 632
 633         cctx->want_tty = buffer_get_int(&m);
 634         cctx->want_subsys = buffer_get_int(&m);
 635         cctx->term = buffer_get_string(&m, &len);
 636
 637         cmd = buffer_get_string(&m, &len);
 638         buffer_init(&cctx->cmd);
 639         buffer_append(&cctx->cmd, cmd, strlen(cmd));
 640
 641         env_len = buffer_get_int(&m);
 642         env_len = MIN(env_len, 4096);
 643         debug3("%s: receiving %d env vars", __func__, env_len);
 644         if (env_len != 0) {
 645                 cctx->env = xmalloc(sizeof(*cctx->env) * (env_len + 1));
 646                 for (i = 0; i < env_len; i++)
 647                         cctx->env[i] = buffer_get_string(&m, &len);
 648                 cctx->env[i] = NULL;
 649         }
 650
 651         debug2("%s: accepted tty %d, subsys %d, cmd %s", __func__,
 652             cctx->want_tty, cctx->want_subsys, cmd);
 653
 654         /* Gather fds from client */
 655         new_fd[0] = mm_receive_fd(client_fd);
 656         new_fd[1] = mm_receive_fd(client_fd);
 657         new_fd[2] = mm_receive_fd(client_fd);
 658
 659         debug2("%s: got fds stdin %d, stdout %d, stderr %d", __func__,
 660             new_fd[0], new_fd[1], new_fd[2]);
 661
 662         /* Try to pick up ttymodes from client before it goes raw */
 663         if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1)
 664                 error("%s: tcgetattr: %s", __func__, strerror(errno));
 665
 666         buffer_clear(&m);
 667         if (ssh_msg_send(client_fd, /* version */0, &m) == -1) {
 668                 error("%s: client msg_send failed", __func__);
 669                 close(client_fd);
 670                 close(new_fd[0]);
 671                 close(new_fd[1]);
 672                 close(new_fd[2]);
 673                 return;
 674         }
 675         buffer_free(&m);
 676
 677         /* enable nonblocking unless tty */
 678         if (!isatty(new_fd[0]))
 679                 set_nonblock(new_fd[0]);
 680         if (!isatty(new_fd[1]))
 681                 set_nonblock(new_fd[1]);
 682         if (!isatty(new_fd[2]))
 683                 set_nonblock(new_fd[2]);
 684
 685         set_nonblock(client_fd);
 686
 687         c = channel_new("session", SSH_CHANNEL_OPENING,
 688             new_fd[0], new_fd[1], new_fd[2],
 689             CHAN_SES_WINDOW_DEFAULT, CHAN_SES_PACKET_DEFAULT,
 690             CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0);
 691
 692         /* XXX */
 693         c->ctl_fd = client_fd;
 694
 695         debug3("%s: channel_new: %d", __func__, c->self);
 696
 697         channel_send_open(c->self);
 698         channel_register_confirm(c->self, client_extra_session2_setup, cctx);
 699 }
 700
 701 static void
 702 process_cmdline(void)
 703 {
 704         void (*handler)(int);
 705         char *s, *cmd;
 706         u_short fwd_port, fwd_host_port;
 707         char buf[1024], sfwd_port[6], sfwd_host_port[6];
 708         int delete = 0;
 709         int local = 0;
 710
 711         leave_raw_mode();
 712         handler = signal(SIGINT, SIG_IGN);
 713         cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
 714         if (s == NULL)
 715                 goto out;
 716         while (*s && isspace(*s))
 717                 s++;
 718         if (*s == '-')
 719                 s++;    /* Skip cmdline '-', if any */
 720         if (*s == '\0')
 721                 goto out;
 722
 723         if (*s == 'h' || *s == 'H' || *s == '?') {
 724                 logit("Commands:");
 725                 logit("      -Lport:host:hostport    Request local forward");
 726                 logit("      -Rport:host:hostport    Request remote forward");
 727                 logit("      -KRhostport             Cancel remote forward");
 728                 goto out;
 729         }
 730
 731         if (*s == 'K') {
 732                 delete = 1;
 733                 s++;
 734         }
 735         if (*s != 'L' && *s != 'R') {
 736                 logit("Invalid command.");
 737                 goto out;
 738         }
 739         if (*s == 'L')
 740                 local = 1;
 741         if (local && delete) {
 742                 logit("Not supported.");
 743                 goto out;
 744         }
 745         if ((!local || delete) && !compat20) {
 746                 logit("Not supported for SSH protocol version 1.");
 747                 goto out;
 748         }
 749
 750         s++;
 751         while (*s && isspace(*s))
 752                 s++;
 753
 754         if (delete) {
 755                 if (sscanf(s, "%5[0-9]", sfwd_host_port) != 1) {
 756                         logit("Bad forwarding specification.");
 757                         goto out;
 758                 }
 759                 if ((fwd_host_port = a2port(sfwd_host_port)) == 0) {
 760                         logit("Bad forwarding port(s).");
 761                         goto out;
 762                 }
 763                 channel_request_rforward_cancel(fwd_host_port);
 764         } else {
 765                 if (sscanf(s, "%5[0-9]:%255[^:]:%5[0-9]",
 766                     sfwd_port, buf, sfwd_host_port) != 3 &&
 767                     sscanf(s, "%5[0-9]/%255[^/]/%5[0-9]",
 768                     sfwd_port, buf, sfwd_host_port) != 3) {
 769                         logit("Bad forwarding specification.");
 770                         goto out;
 771                 }
 772                 if ((fwd_port = a2port(sfwd_port)) == 0 ||
 773                     (fwd_host_port = a2port(sfwd_host_port)) == 0) {
 774                         logit("Bad forwarding port(s).");
 775                         goto out;
 776                 }
 777                 if (local) {
 778                         if (channel_setup_local_fwd_listener(fwd_port, buf,
 779                             fwd_host_port, options.gateway_ports) < 0) {
 780                                 logit("Port forwarding failed.");
 781                                 goto out;
 782                         }
 783                 } else
 784                         channel_request_remote_forwarding(fwd_port, buf,
 785                             fwd_host_port);
 786                 logit("Forwarding port.");
 787         }
 788
 789 out:
 790         signal(SIGINT, handler);
 791         enter_raw_mode();
 792         if (cmd)
 793                 xfree(cmd);
 794 }
 795
 796 /* process the characters one by one */
 797 static int
 798 process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
 799 {
 800         char string[1024];
 801         pid_t pid;
 802         int bytes = 0;
 803         u_int i;
 804         u_char ch;
 805         char *s;
 806
 807         for (i = 0; i < len; i++) {
 808                 /* Get one character at a time. */
 809                 ch = buf[i];
 810
 811                 if (escape_pending) {
 812                         /* We have previously seen an escape character. */
 813                         /* Clear the flag now. */
 814                         escape_pending = 0;
 815
 816                         /* Process the escaped character. */
 817                         switch (ch) {
 818                         case '.':
 819                                 /* Terminate the connection. */
 820                                 snprintf(string, sizeof string, "%c.\r\n", escape_char);
 821                                 buffer_append(berr, string, strlen(string));
 822
 823                                 quit_pending = 1;
 824                                 return -1;
 825
 826                         case 'Z' - 64:
 827                                 /* Suspend the program. */
 828                                 /* Print a message to that effect to the user. */
 829                                 snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char);
 830                                 buffer_append(berr, string, strlen(string));
 831
 832                                 /* Restore terminal modes and suspend. */
 833                                 client_suspend_self(bin, bout, berr);
 834
 835                                 /* We have been continued. */
 836                                 continue;
 837
 838                         case 'B':
 839                                 if (compat20) {
 840                                         snprintf(string, sizeof string,
 841                                             "%cB\r\n", escape_char);
 842                                         buffer_append(berr, string,
 843                                             strlen(string));
 844                                         channel_request_start(session_ident,
 845                                             "break", 0);
 846                                         packet_put_int(1000);
 847                                         packet_send();
 848                                 }
 849                                 continue;
 850
 851                         case 'R':
 852                                 if (compat20) {
 853                                         if (datafellows & SSH_BUG_NOREKEY)
 854                                                 logit("Server does not support re-keying");
 855                                         else
 856                                                 need_rekeying = 1;
 857                                 }
 858                                 continue;
 859
 860                         case '&':
 861                                 /*
 862                                  * Detach the program (continue to serve connections,
 863                                  * but put in background and no more new connections).
 864                                  */
 865                                 /* Restore tty modes. */
 866                                 leave_raw_mode();
 867
 868                                 /* Stop listening for new connections. */
 869                                 channel_stop_listening();
 870
 871                                 snprintf(string, sizeof string,
 872                                     "%c& [backgrounded]\n", escape_char);
 873                                 buffer_append(berr, string, strlen(string));
 874
 875                                 /* Fork into background. */
 876                                 pid = fork();
 877                                 if (pid < 0) {
 878                                         error("fork: %.100s", strerror(errno));
 879                                         continue;
 880                                 }
 881                                 if (pid != 0) { /* This is the parent. */
 882                                         /* The parent just exits. */
 883                                         exit(0);
 884                                 }
 885                                 /* The child continues serving connections. */
 886                                 if (compat20) {
 887                                         buffer_append(bin, "\004", 1);
 888                                         /* fake EOF on stdin */
 889                                         return -1;
 890                                 } else if (!stdin_eof) {
 891                                         /*
 892                                          * Sending SSH_CMSG_EOF alone does not always appear
 893                                          * to be enough.  So we try to send an EOF character
 894                                          * first.
 895                                          */
 896                                         packet_start(SSH_CMSG_STDIN_DATA);
 897                                         packet_put_string("\004", 1);
 898                                         packet_send();
 899                                         /* Close stdin. */
 900                                         stdin_eof = 1;
 901                                         if (buffer_len(bin) == 0) {
 902                                                 packet_start(SSH_CMSG_EOF);
 903                                                 packet_send();
 904                                         }
 905                                 }
 906                                 continue;
 907
 908                         case '?':
 909                                 snprintf(string, sizeof string,
 910 "%c?\r\n\
 911 Supported escape sequences:\r\n\
 912 %c.  - terminate connection\r\n\
 913 %cB  - send a BREAK to the remote system\r\n\
 914 %cC  - open a command line\r\n\
 915 %cR  - Request rekey (SSH protocol 2 only)\r\n\
 916 %c^Z - suspend ssh\r\n\
 917 %c#  - list forwarded connections\r\n\
 918 %c&  - background ssh (when waiting for connections to terminate)\r\n\
 919 %c?  - this message\r\n\
 920 %c%c  - send the escape character by typing it twice\r\n\
 921 (Note that escapes are only recognized immediately after newline.)\r\n",
 922                                     escape_char, escape_char, escape_char, escape_char,
 923                                     escape_char, escape_char, escape_char, escape_char,
 924                                     escape_char, escape_char, escape_char);
 925                                 buffer_append(berr, string, strlen(string));
 926                                 continue;
 927
 928                         case '#':
 929                                 snprintf(string, sizeof string, "%c#\r\n", escape_char);
 930                                 buffer_append(berr, string, strlen(string));
 931                                 s = channel_open_message();
 932                                 buffer_append(berr, s, strlen(s));
 933                                 xfree(s);
 934                                 continue;
 935
 936                         case 'C':
 937                                 process_cmdline();
 938                                 continue;
 939
 940                         default:
 941                                 if (ch != escape_char) {
 942                                         buffer_put_char(bin, escape_char);
 943                                         bytes++;
 944                                 }
 945                                 /* Escaped characters fall through here */
 946                                 break;
 947                         }
 948                 } else {
 949                         /*
 950                          * The previous character was not an escape char. Check if this
 951                          * is an escape.
 952                          */
 953                         if (last_was_cr && ch == escape_char) {
 954                                 /* It is. Set the flag and continue to next character. */
 955                                 escape_pending = 1;
 956                                 continue;
 957                         }
 958                 }
 959
 960                 /*
 961                  * Normal character.  Record whether it was a newline,
 962                  * and append it to the buffer.
 963                  */
 964                 last_was_cr = (ch == '\r' || ch == '\n');
 965                 buffer_put_char(bin, ch);
 966                 bytes++;
 967         }
 968         return bytes;
 969 }
 970
 971 static void
 972 client_process_input(fd_set * readset)
 973 {
 974         int len;
 975         char buf[8192];
 976
 977         /* Read input from stdin. */
 978         if (FD_ISSET(fileno(stdin), readset)) {
 979                 /* Read as much as possible. */
 980                 len = read(fileno(stdin), buf, sizeof(buf));
 981                 if (len < 0 && (errno == EAGAIN || errno == EINTR))
 982                         return;         /* we'll try again later */
 983                 if (len <= 0) {
 984                         /*
 985                          * Received EOF or error.  They are treated
 986                          * similarly, except that an error message is printed
 987                          * if it was an error condition.
 988                          */
 989                         if (len < 0) {
 990                                 snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno));
 991                                 buffer_append(&stderr_buffer, buf, strlen(buf));
 992                         }
 993                         /* Mark that we have seen EOF. */
 994                         stdin_eof = 1;
 995                         /*
 996                          * Send an EOF message to the server unless there is
 997                          * data in the buffer.  If there is data in the
 998                          * buffer, no message will be sent now.  Code
 999                          * elsewhere will send the EOF when the buffer
1000                          * becomes empty if stdin_eof is set.
1001                          */
1002                         if (buffer_len(&stdin_buffer) == 0) {
1003                                 packet_start(SSH_CMSG_EOF);
1004                                 packet_send();
1005                         }
1006                 } else if (escape_char == SSH_ESCAPECHAR_NONE) {
1007                         /*
1008                          * Normal successful read, and no escape character.
1009                          * Just append the data to buffer.
1010                          */
1011                         buffer_append(&stdin_buffer, buf, len);
1012                 } else {
1013                         /*
1014                          * Normal, successful read.  But we have an escape character
1015                          * and have to process the characters one by one.
1016                          */
1017                         if (process_escapes(&stdin_buffer, &stdout_buffer,
1018                             &stderr_buffer, buf, len) == -1)
1019                                 return;
1020                 }
1021         }
1022 }
1023
1024 static void
1025 client_process_output(fd_set * writeset)
1026 {
1027         int len;
1028         char buf[100];
1029
1030         /* Write buffered output to stdout. */
1031         if (FD_ISSET(fileno(stdout), writeset)) {
1032                 /* Write as much data as possible. */
1033                 len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1034                     buffer_len(&stdout_buffer));
1035                 if (len <= 0) {
1036                         if (errno == EINTR || errno == EAGAIN)
1037                                 len = 0;
1038                         else {
1039                                 /*
1040                                  * An error or EOF was encountered.  Put an
1041                                  * error message to stderr buffer.
1042                                  */
1043                                 snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno));
1044                                 buffer_append(&stderr_buffer, buf, strlen(buf));
1045                                 quit_pending = 1;
1046                                 return;
1047                         }
1048                 }
1049                 /* Consume printed data from the buffer. */
1050                 buffer_consume(&stdout_buffer, len);
1051                 stdout_bytes += len;
1052         }
1053         /* Write buffered output to stderr. */
1054         if (FD_ISSET(fileno(stderr), writeset)) {
1055                 /* Write as much data as possible. */
1056                 len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1057                     buffer_len(&stderr_buffer));
1058                 if (len <= 0) {
1059                         if (errno == EINTR || errno == EAGAIN)
1060                                 len = 0;
1061                         else {
1062                                 /* EOF or error, but can't even print error message. */
1063                                 quit_pending = 1;
1064                                 return;
1065                         }
1066                 }
1067                 /* Consume printed characters from the buffer. */
1068                 buffer_consume(&stderr_buffer, len);
1069                 stderr_bytes += len;
1070         }
1071 }
1072
1073 /*
1074  * Get packets from the connection input buffer, and process them as long as
1075  * there are packets available.
1076  *
1077  * Any unknown packets received during the actual
1078  * session cause the session to terminate.  This is
1079  * intended to make debugging easier since no
1080  * confirmations are sent.  Any compatible protocol
1081  * extensions must be negotiated during the
1082  * preparatory phase.
1083  */
1084
1085 static void
1086 client_process_buffered_input_packets(void)
1087 {
1088         dispatch_run(DISPATCH_NONBLOCK, &quit_pending, compat20 ? xxx_kex : NULL);
1089 }
1090
1091 /* scan buf[] for '~' before sending data to the peer */
1092
1093 static int
1094 simple_escape_filter(Channel *c, char *buf, int len)
1095 {
1096         /* XXX we assume c->extended is writeable */
1097         return process_escapes(&c->input, &c->output, &c->extended, buf, len);
1098 }
1099
1100 static void
1101 client_channel_closed(int id, void *arg)
1102 {
1103         channel_cancel_cleanup(id);
1104         session_closed = 1;
1105         leave_raw_mode();
1106 }
1107
1108 /*
1109  * Implements the interactive session with the server.  This is called after
1110  * the user has been authenticated, and a command has been started on the
1111  * remote host.  If escape_char != SSH_ESCAPECHAR_NONE, it is the character
1112  * used as an escape character for terminating or suspending the session.
1113  */
1114
1115 int
1116 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
1117 {
1118         fd_set *readset = NULL, *writeset = NULL;
1119         double start_time, total_time;
1120         int max_fd = 0, max_fd2 = 0, len, rekeying = 0, nalloc = 0;
1121         char buf[100];
1122
1123         debug("Entering interactive session.");
1124
1125         start_time = get_current_time();
1126
1127         /* Initialize variables. */
1128         escape_pending = 0;
1129         last_was_cr = 1;
1130         exit_status = -1;
1131         stdin_eof = 0;
1132         buffer_high = 64 * 1024;
1133         connection_in = packet_get_connection_in();
1134         connection_out = packet_get_connection_out();
1135         max_fd = MAX(connection_in, connection_out);
1136         if (control_fd != -1)
1137                 max_fd = MAX(max_fd, control_fd);
1138
1139         if (!compat20) {
1140                 /* enable nonblocking unless tty */
1141                 if (!isatty(fileno(stdin)))
1142                         set_nonblock(fileno(stdin));
1143                 if (!isatty(fileno(stdout)))
1144                         set_nonblock(fileno(stdout));
1145                 if (!isatty(fileno(stderr)))
1146                         set_nonblock(fileno(stderr));
1147                 max_fd = MAX(max_fd, fileno(stdin));
1148                 max_fd = MAX(max_fd, fileno(stdout));
1149                 max_fd = MAX(max_fd, fileno(stderr));
1150         }
1151         stdin_bytes = 0;
1152         stdout_bytes = 0;
1153         stderr_bytes = 0;
1154         quit_pending = 0;
1155         escape_char = escape_char_arg;
1156
1157         /* Initialize buffers. */
1158         buffer_init(&stdin_buffer);
1159         buffer_init(&stdout_buffer);
1160         buffer_init(&stderr_buffer);
1161
1162         client_init_dispatch();
1163
1164         /*
1165          * Set signal handlers, (e.g. to restore non-blocking mode)
1166          * but don't overwrite SIG_IGN, matches behaviour from rsh(1)
1167          */
1168         if (signal(SIGINT, SIG_IGN) != SIG_IGN)
1169                 signal(SIGINT, signal_handler);
1170         if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
1171                 signal(SIGQUIT, signal_handler);
1172         if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
1173                 signal(SIGTERM, signal_handler);
1174         if (have_pty)
1175                 signal(SIGWINCH, window_change_handler);
1176
1177         if (have_pty)
1178                 enter_raw_mode();
1179
1180         if (compat20) {
1181                 session_ident = ssh2_chan_id;
1182                 if (escape_char != SSH_ESCAPECHAR_NONE)
1183                         channel_register_filter(session_ident,
1184                             simple_escape_filter);
1185                 if (session_ident != -1)
1186                         channel_register_cleanup(session_ident,
1187                             client_channel_closed);
1188         } else {
1189                 /* Check if we should immediately send eof on stdin. */
1190                 client_check_initial_eof_on_stdin();
1191         }
1192
1193         /* Main loop of the client for the interactive session mode. */
1194         while (!quit_pending) {
1195
1196                 /* Process buffered packets sent by the server. */
1197                 client_process_buffered_input_packets();
1198
1199                 if (compat20 && session_closed && !channel_still_open())
1200                         break;
1201
1202                 rekeying = (xxx_kex != NULL && !xxx_kex->done);
1203
1204                 if (rekeying) {
1205                         debug("rekeying in progress");
1206                 } else {
1207                         /*
1208                          * Make packets of buffered stdin data, and buffer
1209                          * them for sending to the server.
1210                          */
1211                         if (!compat20)
1212                                 client_make_packets_from_stdin_data();
1213
1214                         /*
1215                          * Make packets from buffered channel data, and
1216                          * enqueue them for sending to the server.
1217                          */
1218                         if (packet_not_very_much_data_to_write())
1219                                 channel_output_poll();
1220
1221                         /*
1222                          * Check if the window size has changed, and buffer a
1223                          * message about it to the server if so.
1224                          */
1225                         client_check_window_change();
1226
1227                         if (quit_pending)
1228                                 break;
1229                 }
1230                 /*
1231                  * Wait until we have something to do (something becomes
1232                  * available on one of the descriptors).
1233                  */
1234                 max_fd2 = max_fd;
1235                 client_wait_until_can_do_something(&readset, &writeset,
1236                     &max_fd2, &nalloc, rekeying);
1237
1238                 if (quit_pending)
1239                         break;
1240
1241                 /* Do channel operations unless rekeying in progress. */
1242                 if (!rekeying) {
1243                         channel_after_select(readset, writeset);
1244                         if (need_rekeying || packet_need_rekeying()) {
1245                                 debug("need rekeying");
1246                                 xxx_kex->done = 0;
1247                                 kex_send_kexinit(xxx_kex);
1248                                 need_rekeying = 0;
1249                         }
1250                 }
1251
1252                 /* Buffer input from the connection.  */
1253                 client_process_net_input(readset);
1254
1255                 /* Accept control connections.  */
1256                 client_process_control(readset);
1257
1258                 if (quit_pending)
1259                         break;
1260
1261                 if (!compat20) {
1262                         /* Buffer data from stdin */
1263                         client_process_input(readset);
1264                         /*
1265                          * Process output to stdout and stderr.  Output to
1266                          * the connection is processed elsewhere (above).
1267                          */
1268                         client_process_output(writeset);
1269                 }
1270
1271                 /* Send as much buffered packet data as possible to the sender. */
1272                 if (FD_ISSET(connection_out, writeset))
1273                         packet_write_poll();
1274         }
1275         if (readset)
1276                 xfree(readset);
1277         if (writeset)
1278                 xfree(writeset);
1279
1280         /* Terminate the session. */
1281
1282         /* Stop watching for window change. */
1283         if (have_pty)
1284                 signal(SIGWINCH, SIG_DFL);
1285
1286         channel_free_all();
1287
1288         if (have_pty)
1289                 leave_raw_mode();
1290
1291         /* restore blocking io */
1292         if (!isatty(fileno(stdin)))
1293                 unset_nonblock(fileno(stdin));
1294         if (!isatty(fileno(stdout)))
1295                 unset_nonblock(fileno(stdout));
1296         if (!isatty(fileno(stderr)))
1297                 unset_nonblock(fileno(stderr));
1298
1299         /*
1300          * If there was no shell or command requested, there will be no remote
1301          * exit status to be returned.  In that case, clear error code if the
1302          * connection was deliberately terminated at this end.
1303          */
1304         if (no_shell_flag && received_signal == SIGTERM) {
1305                 received_signal = 0;
1306                 exit_status = 0;
1307         }
1308
1309         if (received_signal)
1310                 fatal("Killed by signal %d.", (int) received_signal);
1311
1312         /*
1313          * In interactive mode (with pseudo tty) display a message indicating
1314          * that the connection has been closed.
1315          */
1316         if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
1317                 snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host);
1318                 buffer_append(&stderr_buffer, buf, strlen(buf));
1319         }
1320
1321         /* Output any buffered data for stdout. */
1322         while (buffer_len(&stdout_buffer) > 0) {
1323                 len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1324                     buffer_len(&stdout_buffer));
1325                 if (len <= 0) {
1326                         error("Write failed flushing stdout buffer.");
1327                         break;
1328                 }
1329                 buffer_consume(&stdout_buffer, len);
1330                 stdout_bytes += len;
1331         }
1332
1333         /* Output any buffered data for stderr. */
1334         while (buffer_len(&stderr_buffer) > 0) {
1335                 len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1336                     buffer_len(&stderr_buffer));
1337                 if (len <= 0) {
1338                         error("Write failed flushing stderr buffer.");
1339                         break;
1340                 }
1341                 buffer_consume(&stderr_buffer, len);
1342                 stderr_bytes += len;
1343         }
1344
1345         /* Clear and free any buffers. */
1346         memset(buf, 0, sizeof(buf));
1347         buffer_free(&stdin_buffer);
1348         buffer_free(&stdout_buffer);
1349         buffer_free(&stderr_buffer);
1350
1351         /* Report bytes transferred, and transfer rates. */
1352         total_time = get_current_time() - start_time;
1353         debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
1354             stdin_bytes, stdout_bytes, stderr_bytes, total_time);
1355         if (total_time > 0)
1356                 debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
1357                     stdin_bytes / total_time, stdout_bytes / total_time,
1358                     stderr_bytes / total_time);
1359
1360         /* Return the exit status of the program. */
1361         debug("Exit status %d", exit_status);
1362         return exit_status;
1363 }
1364
1365 /*********/
1366
1367 static void
1368 client_input_stdout_data(int type, u_int32_t seq, void *ctxt)
1369 {
1370         u_int data_len;
1371         char *data = packet_get_string(&data_len);
1372         packet_check_eom();
1373         buffer_append(&stdout_buffer, data, data_len);
1374         memset(data, 0, data_len);
1375         xfree(data);
1376 }
1377 static void
1378 client_input_stderr_data(int type, u_int32_t seq, void *ctxt)
1379 {
1380         u_int data_len;
1381         char *data = packet_get_string(&data_len);
1382         packet_check_eom();
1383         buffer_append(&stderr_buffer, data, data_len);
1384         memset(data, 0, data_len);
1385         xfree(data);
1386 }
1387 static void
1388 client_input_exit_status(int type, u_int32_t seq, void *ctxt)
1389 {
1390         exit_status = packet_get_int();
1391         packet_check_eom();
1392         /* Acknowledge the exit. */
1393         packet_start(SSH_CMSG_EXIT_CONFIRMATION);
1394         packet_send();
1395         /*
1396          * Must wait for packet to be sent since we are
1397          * exiting the loop.
1398          */
1399         packet_write_wait();
1400         /* Flag that we want to exit. */
1401         quit_pending = 1;
1402 }
1403 static void
1404 client_input_agent_open(int type, u_int32_t seq, void *ctxt)
1405 {
1406         Channel *c = NULL;
1407         int remote_id, sock;
1408
1409         /* Read the remote channel number from the message. */
1410         remote_id = packet_get_int();
1411         packet_check_eom();
1412
1413         /*
1414          * Get a connection to the local authentication agent (this may again
1415          * get forwarded).
1416          */
1417         sock = ssh_get_authentication_socket();
1418
1419         /*
1420          * If we could not connect the agent, send an error message back to
1421          * the server. This should never happen unless the agent dies,
1422          * because authentication forwarding is only enabled if we have an
1423          * agent.
1424          */
1425         if (sock >= 0) {
1426                 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
1427                     -1, 0, 0, 0, "authentication agent connection", 1);
1428                 c->remote_id = remote_id;
1429                 c->force_drain = 1;
1430         }
1431         if (c == NULL) {
1432                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1433                 packet_put_int(remote_id);
1434         } else {
1435                 /* Send a confirmation to the remote host. */
1436                 debug("Forwarding authentication connection.");
1437                 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1438                 packet_put_int(remote_id);
1439                 packet_put_int(c->self);
1440         }
1441         packet_send();
1442 }
1443
1444 static Channel *
1445 client_request_forwarded_tcpip(const char *request_type, int rchan)
1446 {
1447         Channel *c = NULL;
1448         char *listen_address, *originator_address;
1449         int listen_port, originator_port;
1450         int sock;
1451
1452         /* Get rest of the packet */
1453         listen_address = packet_get_string(NULL);
1454         listen_port = packet_get_int();
1455         originator_address = packet_get_string(NULL);
1456         originator_port = packet_get_int();
1457         packet_check_eom();
1458
1459         debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d",
1460             listen_address, listen_port, originator_address, originator_port);
1461
1462         sock = channel_connect_by_listen_address(listen_port);
1463         if (sock < 0) {
1464                 xfree(originator_address);
1465                 xfree(listen_address);
1466                 return NULL;
1467         }
1468         c = channel_new("forwarded-tcpip",
1469             SSH_CHANNEL_CONNECTING, sock, sock, -1,
1470             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
1471             originator_address, 1);
1472         xfree(originator_address);
1473         xfree(listen_address);
1474         return c;
1475 }
1476
1477 static Channel *
1478 client_request_x11(const char *request_type, int rchan)
1479 {
1480         Channel *c = NULL;
1481         char *originator;
1482         int originator_port;
1483         int sock;
1484
1485         if (!options.forward_x11) {
1486                 error("Warning: ssh server tried X11 forwarding.");
1487                 error("Warning: this is probably a break in attempt by a malicious server.");
1488                 return NULL;
1489         }
1490         originator = packet_get_string(NULL);
1491         if (datafellows & SSH_BUG_X11FWD) {
1492                 debug2("buggy server: x11 request w/o originator_port");
1493                 originator_port = 0;
1494         } else {
1495                 originator_port = packet_get_int();
1496         }
1497         packet_check_eom();
1498         /* XXX check permission */
1499         debug("client_request_x11: request from %s %d", originator,
1500             originator_port);
1501         xfree(originator);
1502         sock = x11_connect_display();
1503         if (sock < 0)
1504                 return NULL;
1505         c = channel_new("x11",
1506             SSH_CHANNEL_X11_OPEN, sock, sock, -1,
1507             CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1);
1508         c->force_drain = 1;
1509         return c;
1510 }
1511
1512 static Channel *
1513 client_request_agent(const char *request_type, int rchan)
1514 {
1515         Channel *c = NULL;
1516         int sock;
1517
1518         if (!options.forward_agent) {
1519                 error("Warning: ssh server tried agent forwarding.");
1520                 error("Warning: this is probably a break in attempt by a malicious server.");
1521                 return NULL;
1522         }
1523         sock =  ssh_get_authentication_socket();
1524         if (sock < 0)
1525                 return NULL;
1526         c = channel_new("authentication agent connection",
1527             SSH_CHANNEL_OPEN, sock, sock, -1,
1528             CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
1529             "authentication agent connection", 1);
1530         c->force_drain = 1;
1531         return c;
1532 }
1533
1534 /* XXXX move to generic input handler */
1535 static void
1536 client_input_channel_open(int type, u_int32_t seq, void *ctxt)
1537 {
1538         Channel *c = NULL;
1539         char *ctype;
1540         int rchan;
1541         u_int rmaxpack, rwindow, len;
1542
1543         ctype = packet_get_string(&len);
1544         rchan = packet_get_int();
1545         rwindow = packet_get_int();
1546         rmaxpack = packet_get_int();
1547
1548         debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
1549             ctype, rchan, rwindow, rmaxpack);
1550
1551         if (strcmp(ctype, "forwarded-tcpip") == 0) {
1552                 c = client_request_forwarded_tcpip(ctype, rchan);
1553         } else if (strcmp(ctype, "x11") == 0) {
1554                 c = client_request_x11(ctype, rchan);
1555         } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) {
1556                 c = client_request_agent(ctype, rchan);
1557         }
1558 /* XXX duplicate : */
1559         if (c != NULL) {
1560                 debug("confirm %s", ctype);
1561                 c->remote_id = rchan;
1562                 c->remote_window = rwindow;
1563                 c->remote_maxpacket = rmaxpack;
1564                 if (c->type != SSH_CHANNEL_CONNECTING) {
1565                         packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1566                         packet_put_int(c->remote_id);
1567                         packet_put_int(c->self);
1568                         packet_put_int(c->local_window);
1569                         packet_put_int(c->local_maxpacket);
1570                         packet_send();
1571                 }
1572         } else {
1573                 debug("failure %s", ctype);
1574                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1575                 packet_put_int(rchan);
1576                 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1577                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1578                         packet_put_cstring("open failed");
1579                         packet_put_cstring("");
1580                 }
1581                 packet_send();
1582         }
1583         xfree(ctype);
1584 }
1585 static void
1586 client_input_channel_req(int type, u_int32_t seq, void *ctxt)
1587 {
1588         Channel *c = NULL;
1589         int exitval, id, reply, success = 0;
1590         char *rtype;
1591
1592         id = packet_get_int();
1593         rtype = packet_get_string(NULL);
1594         reply = packet_get_char();
1595
1596         debug("client_input_channel_req: channel %d rtype %s reply %d",
1597             id, rtype, reply);
1598
1599         c = channel_lookup(id);
1600         if (c == NULL) {
1601                 error("client_input_channel_req: channel %d: unknown channel", id);
1602         } else if (strcmp(rtype, "exit-status") == 0) {
1603                 exitval = packet_get_int();
1604                 if (id == session_ident) {
1605                         success = 1;
1606                         exit_status = exitval;
1607                 } else if (c->ctl_fd == -1) {
1608                         error("client_input_channel_req: unexpected channel %d",
1609                             session_ident);
1610                 } else {
1611                         atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval));
1612                         success = 1;
1613                 }
1614                 packet_check_eom();
1615         }
1616         if (reply) {
1617                 packet_start(success ?
1618                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1619                 packet_put_int(c->remote_id);
1620                 packet_send();
1621         }
1622         xfree(rtype);
1623 }
1624 static void
1625 client_input_global_request(int type, u_int32_t seq, void *ctxt)
1626 {
1627         char *rtype;
1628         int want_reply;
1629         int success = 0;
1630
1631         rtype = packet_get_string(NULL);
1632         want_reply = packet_get_char();
1633         debug("client_input_global_request: rtype %s want_reply %d",
1634             rtype, want_reply);
1635         if (want_reply) {
1636                 packet_start(success ?
1637                     SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1638                 packet_send();
1639                 packet_write_wait();
1640         }
1641         xfree(rtype);
1642 }
1643
1644 void
1645 client_session2_setup(int id, int want_tty, int want_subsystem,
1646     const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env,
1647     dispatch_fn *subsys_repl)
1648 {
1649         int len;
1650
1651         debug2("%s: id %d", __func__, id);
1652
1653         if (want_tty) {
1654                 struct winsize ws;
1655                 struct termios tio;
1656
1657                 /* Store window size in the packet. */
1658                 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0)
1659                         memset(&ws, 0, sizeof(ws));
1660
1661                 channel_request_start(id, "pty-req", 0);
1662                 packet_put_cstring(term != NULL ? term : "");
1663                 packet_put_int(ws.ws_col);
1664                 packet_put_int(ws.ws_row);
1665                 packet_put_int(ws.ws_xpixel);
1666                 packet_put_int(ws.ws_ypixel);
1667                 tio = get_saved_tio();
1668                 tty_make_modes(-1, tiop != NULL ? tiop : &tio);
1669                 packet_send();
1670                 /* XXX wait for reply */
1671         }
1672
1673         /* Transfer any environment variables from client to server */
1674         if (options.num_send_env != 0 && env != NULL) {
1675                 int i, j, matched;
1676                 char *name, *val;
1677
1678                 debug("Sending environment.");
1679                 for (i = 0; env[i] != NULL; i++) {
1680                         /* Split */
1681                         name = xstrdup(env[i]);
1682                         if ((val = strchr(name, '=')) == NULL) {
1683                                 free(name);
1684                                 continue;
1685                         }
1686                         *val++ = '\0';
1687
1688                         matched = 0;
1689                         for (j = 0; j < options.num_send_env; j++) {
1690                                 if (match_pattern(name, options.send_env[j])) {
1691                                         matched = 1;
1692                                         break;
1693                                 }
1694                         }
1695                         if (!matched) {
1696                                 debug3("Ignored env %s", name);
1697                                 free(name);
1698                                 continue;
1699                         }
1700
1701                         debug("Sending env %s = %s", name, val);
1702                         channel_request_start(id, "env", 0);
1703                         packet_put_cstring(name);
1704                         packet_put_cstring(val);
1705                         packet_send();
1706                         free(name);
1707                 }
1708         }
1709
1710         len = buffer_len(cmd);
1711         if (len > 0) {
1712                 if (len > 900)
1713                         len = 900;
1714                 if (want_subsystem) {
1715                         debug("Sending subsystem: %.*s", len, (u_char*)buffer_ptr(cmd));
1716                         channel_request_start(id, "subsystem", subsys_repl != NULL);
1717                         if (subsys_repl != NULL) {
1718                                 /* register callback for reply */
1719                                 /* XXX we assume that client_loop has already been called */
1720                                 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, subsys_repl);
1721                                 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, subsys_repl);
1722                         }
1723                 } else {
1724                         debug("Sending command: %.*s", len, (u_char*)buffer_ptr(cmd));
1725                         channel_request_start(id, "exec", 0);
1726                 }
1727                 packet_put_string(buffer_ptr(cmd), buffer_len(cmd));
1728                 packet_send();
1729         } else {
1730                 channel_request_start(id, "shell", 0);
1731                 packet_send();
1732         }
1733 }
1734
1735 static void
1736 client_init_dispatch_20(void)
1737 {
1738         dispatch_init(&dispatch_protocol_error);
1739
1740         dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1741         dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1742         dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1743         dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1744         dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
1745         dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1746         dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1747         dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
1748         dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1749         dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);
1750
1751         /* rekeying */
1752         dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1753
1754         /* global request reply messages */
1755         dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
1756         dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
1757 }
1758 static void
1759 client_init_dispatch_13(void)
1760 {
1761         dispatch_init(NULL);
1762         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1763         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1764         dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1765         dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1766         dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1767         dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1768         dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
1769         dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
1770         dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);
1771
1772         dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ?
1773             &client_input_agent_open : &deny_input_open);
1774         dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ?
1775             &x11_input_open : &deny_input_open);
1776 }
1777 static void
1778 client_init_dispatch_15(void)
1779 {
1780         client_init_dispatch_13();
1781         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1782         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
1783 }
1784 static void
1785 client_init_dispatch(void)
1786 {
1787         if (compat20)
1788                 client_init_dispatch_20();
1789         else if (compat13)
1790                 client_init_dispatch_13();
1791         else
1792                 client_init_dispatch_15();
1793 }
1794
1795 /* client specific fatal cleanup */
1796 void
1797 cleanup_exit(int i)
1798 {
1799         leave_raw_mode();
1800         leave_non_blocking();
1801         if (options.control_path != NULL && control_fd != -1)
1802                 unlink(options.control_path);
1803         _exit(i);
1804 }