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 1.132 2004/10/29 21:47:15 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;
 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         allowed = 1;
 595         if (options.control_master == 2) {
 596                 char *p, prompt[1024];
 597
 598                 allowed = 0;
 599                 snprintf(prompt, sizeof(prompt),
 600                     "Allow shared connection to %s? ", host);
 601                 p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF);
 602                 if (p != NULL) {
 603                         /*
 604                          * Accept empty responses and responses consisting
 605                          * of the word "yes" as affirmative.
 606                          */
 607                         if (*p == '\0' || *p == '\n' ||
 608                             strcasecmp(p, "yes") == 0)
 609                                 allowed = 1;
 610                         xfree(p);
 611                 }
 612         }
 613
 614         unset_nonblock(client_fd);
 615
 616         buffer_init(&m);
 617
 618         buffer_put_int(&m, allowed);
 619         buffer_put_int(&m, getpid());
 620         if (ssh_msg_send(client_fd, /* version */0, &m) == -1) {
 621                 error("%s: client msg_send failed", __func__);
 622                 close(client_fd);
 623                 buffer_free(&m);
 624                 return;
 625         }
 626         buffer_clear(&m);
 627
 628         if (!allowed) {
 629                 error("Refused control connection");
 630                 close(client_fd);
 631                 buffer_free(&m);
 632                 return;
 633         }
 634
 635         if (ssh_msg_recv(client_fd, &m) == -1) {
 636                 error("%s: client msg_recv failed", __func__);
 637                 close(client_fd);
 638                 buffer_free(&m);
 639                 return;
 640         }
 641
 642         if ((ver = buffer_get_char(&m)) != 0) {
 643                 error("%s: wrong client version %d", __func__, ver);
 644                 buffer_free(&m);
 645                 close(client_fd);
 646                 return;
 647         }
 648
 649         cctx = xmalloc(sizeof(*cctx));
 650         memset(cctx, 0, sizeof(*cctx));
 651
 652         cctx->want_tty = buffer_get_int(&m);
 653         cctx->want_subsys = buffer_get_int(&m);
 654         cctx->term = buffer_get_string(&m, &len);
 655
 656         cmd = buffer_get_string(&m, &len);
 657         buffer_init(&cctx->cmd);
 658         buffer_append(&cctx->cmd, cmd, strlen(cmd));
 659
 660         env_len = buffer_get_int(&m);
 661         env_len = MIN(env_len, 4096);
 662         debug3("%s: receiving %d env vars", __func__, env_len);
 663         if (env_len != 0) {
 664                 cctx->env = xmalloc(sizeof(*cctx->env) * (env_len + 1));
 665                 for (i = 0; i < env_len; i++)
 666                         cctx->env[i] = buffer_get_string(&m, &len);
 667                 cctx->env[i] = NULL;
 668         }
 669
 670         debug2("%s: accepted tty %d, subsys %d, cmd %s", __func__,
 671             cctx->want_tty, cctx->want_subsys, cmd);
 672
 673         /* Gather fds from client */
 674         new_fd[0] = mm_receive_fd(client_fd);
 675         new_fd[1] = mm_receive_fd(client_fd);
 676         new_fd[2] = mm_receive_fd(client_fd);
 677
 678         debug2("%s: got fds stdin %d, stdout %d, stderr %d", __func__,
 679             new_fd[0], new_fd[1], new_fd[2]);
 680
 681         /* Try to pick up ttymodes from client before it goes raw */
 682         if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1)
 683                 error("%s: tcgetattr: %s", __func__, strerror(errno));
 684
 685         buffer_clear(&m);
 686         if (ssh_msg_send(client_fd, /* version */0, &m) == -1) {
 687                 error("%s: client msg_send failed", __func__);
 688                 close(client_fd);
 689                 close(new_fd[0]);
 690                 close(new_fd[1]);
 691                 close(new_fd[2]);
 692                 buffer_free(&m);
 693                 return;
 694         }
 695         buffer_free(&m);
 696
 697         /* enable nonblocking unless tty */
 698         if (!isatty(new_fd[0]))
 699                 set_nonblock(new_fd[0]);
 700         if (!isatty(new_fd[1]))
 701                 set_nonblock(new_fd[1]);
 702         if (!isatty(new_fd[2]))
 703                 set_nonblock(new_fd[2]);
 704
 705         set_nonblock(client_fd);
 706
 707         c = channel_new("session", SSH_CHANNEL_OPENING,
 708             new_fd[0], new_fd[1], new_fd[2],
 709             CHAN_SES_WINDOW_DEFAULT, CHAN_SES_PACKET_DEFAULT,
 710             CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0);
 711
 712         /* XXX */
 713         c->ctl_fd = client_fd;
 714
 715         debug3("%s: channel_new: %d", __func__, c->self);
 716
 717         channel_send_open(c->self);
 718         channel_register_confirm(c->self, client_extra_session2_setup, cctx);
 719 }
 720
 721 static void
 722 process_cmdline(void)
 723 {
 724         void (*handler)(int);
 725         char *s, *cmd;
 726         u_short fwd_port, fwd_host_port;
 727         char buf[1024], sfwd_port[6], sfwd_host_port[6];
 728         int delete = 0;
 729         int local = 0;
 730
 731         leave_raw_mode();
 732         handler = signal(SIGINT, SIG_IGN);
 733         cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
 734         if (s == NULL)
 735                 goto out;
 736         while (*s && isspace(*s))
 737                 s++;
 738         if (*s == '-')
 739                 s++;    /* Skip cmdline '-', if any */
 740         if (*s == '\0')
 741                 goto out;
 742
 743         if (*s == 'h' || *s == 'H' || *s == '?') {
 744                 logit("Commands:");
 745                 logit("      -Lport:host:hostport    Request local forward");
 746                 logit("      -Rport:host:hostport    Request remote forward");
 747                 logit("      -KRhostport             Cancel remote forward");
 748                 goto out;
 749         }
 750
 751         if (*s == 'K') {
 752                 delete = 1;
 753                 s++;
 754         }
 755         if (*s != 'L' && *s != 'R') {
 756                 logit("Invalid command.");
 757                 goto out;
 758         }
 759         if (*s == 'L')
 760                 local = 1;
 761         if (local && delete) {
 762                 logit("Not supported.");
 763                 goto out;
 764         }
 765         if ((!local || delete) && !compat20) {
 766                 logit("Not supported for SSH protocol version 1.");
 767                 goto out;
 768         }
 769
 770         s++;
 771         while (*s && isspace(*s))
 772                 s++;
 773
 774         if (delete) {
 775                 if (sscanf(s, "%5[0-9]", sfwd_host_port) != 1) {
 776                         logit("Bad forwarding specification.");
 777                         goto out;
 778                 }
 779                 if ((fwd_host_port = a2port(sfwd_host_port)) == 0) {
 780                         logit("Bad forwarding port(s).");
 781                         goto out;
 782                 }
 783                 channel_request_rforward_cancel(fwd_host_port);
 784         } else {
 785                 if (sscanf(s, "%5[0-9]:%255[^:]:%5[0-9]",
 786                     sfwd_port, buf, sfwd_host_port) != 3 &&
 787                     sscanf(s, "%5[0-9]/%255[^/]/%5[0-9]",
 788                     sfwd_port, buf, sfwd_host_port) != 3) {
 789                         logit("Bad forwarding specification.");
 790                         goto out;
 791                 }
 792                 if ((fwd_port = a2port(sfwd_port)) == 0 ||
 793                     (fwd_host_port = a2port(sfwd_host_port)) == 0) {
 794                         logit("Bad forwarding port(s).");
 795                         goto out;
 796                 }
 797                 if (local) {
 798                         if (channel_setup_local_fwd_listener(fwd_port, buf,
 799                             fwd_host_port, options.gateway_ports) < 0) {
 800                                 logit("Port forwarding failed.");
 801                                 goto out;
 802                         }
 803                 } else
 804                         channel_request_remote_forwarding(fwd_port, buf,
 805                             fwd_host_port);
 806                 logit("Forwarding port.");
 807         }
 808
 809 out:
 810         signal(SIGINT, handler);
 811         enter_raw_mode();
 812         if (cmd)
 813                 xfree(cmd);
 814 }
 815
 816 /* process the characters one by one */
 817 static int
 818 process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
 819 {
 820         char string[1024];
 821         pid_t pid;
 822         int bytes = 0;
 823         u_int i;
 824         u_char ch;
 825         char *s;
 826
 827         for (i = 0; i < len; i++) {
 828                 /* Get one character at a time. */
 829                 ch = buf[i];
 830
 831                 if (escape_pending) {
 832                         /* We have previously seen an escape character. */
 833                         /* Clear the flag now. */
 834                         escape_pending = 0;
 835
 836                         /* Process the escaped character. */
 837                         switch (ch) {
 838                         case '.':
 839                                 /* Terminate the connection. */
 840                                 snprintf(string, sizeof string, "%c.\r\n", escape_char);
 841                                 buffer_append(berr, string, strlen(string));
 842
 843                                 quit_pending = 1;
 844                                 return -1;
 845
 846                         case 'Z' - 64:
 847                                 /* Suspend the program. */
 848                                 /* Print a message to that effect to the user. */
 849                                 snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char);
 850                                 buffer_append(berr, string, strlen(string));
 851
 852                                 /* Restore terminal modes and suspend. */
 853                                 client_suspend_self(bin, bout, berr);
 854
 855                                 /* We have been continued. */
 856                                 continue;
 857
 858                         case 'B':
 859                                 if (compat20) {
 860                                         snprintf(string, sizeof string,
 861                                             "%cB\r\n", escape_char);
 862                                         buffer_append(berr, string,
 863                                             strlen(string));
 864                                         channel_request_start(session_ident,
 865                                             "break", 0);
 866                                         packet_put_int(1000);
 867                                         packet_send();
 868                                 }
 869                                 continue;
 870
 871                         case 'R':
 872                                 if (compat20) {
 873                                         if (datafellows & SSH_BUG_NOREKEY)
 874                                                 logit("Server does not support re-keying");
 875                                         else
 876                                                 need_rekeying = 1;
 877                                 }
 878                                 continue;
 879
 880                         case '&':
 881                                 /*
 882                                  * Detach the program (continue to serve connections,
 883                                  * but put in background and no more new connections).
 884                                  */
 885                                 /* Restore tty modes. */
 886                                 leave_raw_mode();
 887
 888                                 /* Stop listening for new connections. */
 889                                 channel_stop_listening();
 890
 891                                 snprintf(string, sizeof string,
 892                                     "%c& [backgrounded]\n", escape_char);
 893                                 buffer_append(berr, string, strlen(string));
 894
 895                                 /* Fork into background. */
 896                                 pid = fork();
 897                                 if (pid < 0) {
 898                                         error("fork: %.100s", strerror(errno));
 899                                         continue;
 900                                 }
 901                                 if (pid != 0) { /* This is the parent. */
 902                                         /* The parent just exits. */
 903                                         exit(0);
 904                                 }
 905                                 /* The child continues serving connections. */
 906                                 if (compat20) {
 907                                         buffer_append(bin, "\004", 1);
 908                                         /* fake EOF on stdin */
 909                                         return -1;
 910                                 } else if (!stdin_eof) {
 911                                         /*
 912                                          * Sending SSH_CMSG_EOF alone does not always appear
 913                                          * to be enough.  So we try to send an EOF character
 914                                          * first.
 915                                          */
 916                                         packet_start(SSH_CMSG_STDIN_DATA);
 917                                         packet_put_string("\004", 1);
 918                                         packet_send();
 919                                         /* Close stdin. */
 920                                         stdin_eof = 1;
 921                                         if (buffer_len(bin) == 0) {
 922                                                 packet_start(SSH_CMSG_EOF);
 923                                                 packet_send();
 924                                         }
 925                                 }
 926                                 continue;
 927
 928                         case '?':
 929                                 snprintf(string, sizeof string,
 930 "%c?\r\n\
 931 Supported escape sequences:\r\n\
 932 %c.  - terminate connection\r\n\
 933 %cB  - send a BREAK to the remote system\r\n\
 934 %cC  - open a command line\r\n\
 935 %cR  - Request rekey (SSH protocol 2 only)\r\n\
 936 %c^Z - suspend ssh\r\n\
 937 %c#  - list forwarded connections\r\n\
 938 %c&  - background ssh (when waiting for connections to terminate)\r\n\
 939 %c?  - this message\r\n\
 940 %c%c  - send the escape character by typing it twice\r\n\
 941 (Note that escapes are only recognized immediately after newline.)\r\n",
 942                                     escape_char, escape_char, escape_char, escape_char,
 943                                     escape_char, escape_char, escape_char, escape_char,
 944                                     escape_char, escape_char, escape_char);
 945                                 buffer_append(berr, string, strlen(string));
 946                                 continue;
 947
 948                         case '#':
 949                                 snprintf(string, sizeof string, "%c#\r\n", escape_char);
 950                                 buffer_append(berr, string, strlen(string));
 951                                 s = channel_open_message();
 952                                 buffer_append(berr, s, strlen(s));
 953                                 xfree(s);
 954                                 continue;
 955
 956                         case 'C':
 957                                 process_cmdline();
 958                                 continue;
 959
 960                         default:
 961                                 if (ch != escape_char) {
 962                                         buffer_put_char(bin, escape_char);
 963                                         bytes++;
 964                                 }
 965                                 /* Escaped characters fall through here */
 966                                 break;
 967                         }
 968                 } else {
 969                         /*
 970                          * The previous character was not an escape char. Check if this
 971                          * is an escape.
 972                          */
 973                         if (last_was_cr && ch == escape_char) {
 974                                 /* It is. Set the flag and continue to next character. */
 975                                 escape_pending = 1;
 976                                 continue;
 977                         }
 978                 }
 979
 980                 /*
 981                  * Normal character.  Record whether it was a newline,
 982                  * and append it to the buffer.
 983                  */
 984                 last_was_cr = (ch == '\r' || ch == '\n');
 985                 buffer_put_char(bin, ch);
 986                 bytes++;
 987         }
 988         return bytes;
 989 }
 990
 991 static void
 992 client_process_input(fd_set * readset)
 993 {
 994         int len;
 995         char buf[8192];
 996
 997         /* Read input from stdin. */
 998         if (FD_ISSET(fileno(stdin), readset)) {
 999                 /* Read as much as possible. */
1000                 len = read(fileno(stdin), buf, sizeof(buf));
1001                 if (len < 0 && (errno == EAGAIN || errno == EINTR))
1002                         return;         /* we'll try again later */
1003                 if (len <= 0) {
1004                         /*
1005                          * Received EOF or error.  They are treated
1006                          * similarly, except that an error message is printed
1007                          * if it was an error condition.
1008                          */
1009                         if (len < 0) {
1010                                 snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno));
1011                                 buffer_append(&stderr_buffer, buf, strlen(buf));
1012                         }
1013                         /* Mark that we have seen EOF. */
1014                         stdin_eof = 1;
1015                         /*
1016                          * Send an EOF message to the server unless there is
1017                          * data in the buffer.  If there is data in the
1018                          * buffer, no message will be sent now.  Code
1019                          * elsewhere will send the EOF when the buffer
1020                          * becomes empty if stdin_eof is set.
1021                          */
1022                         if (buffer_len(&stdin_buffer) == 0) {
1023                                 packet_start(SSH_CMSG_EOF);
1024                                 packet_send();
1025                         }
1026                 } else if (escape_char == SSH_ESCAPECHAR_NONE) {
1027                         /*
1028                          * Normal successful read, and no escape character.
1029                          * Just append the data to buffer.
1030                          */
1031                         buffer_append(&stdin_buffer, buf, len);
1032                 } else {
1033                         /*
1034                          * Normal, successful read.  But we have an escape character
1035                          * and have to process the characters one by one.
1036                          */
1037                         if (process_escapes(&stdin_buffer, &stdout_buffer,
1038                             &stderr_buffer, buf, len) == -1)
1039                                 return;
1040                 }
1041         }
1042 }
1043
1044 static void
1045 client_process_output(fd_set * writeset)
1046 {
1047         int len;
1048         char buf[100];
1049
1050         /* Write buffered output to stdout. */
1051         if (FD_ISSET(fileno(stdout), writeset)) {
1052                 /* Write as much data as possible. */
1053                 len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1054                     buffer_len(&stdout_buffer));
1055                 if (len <= 0) {
1056                         if (errno == EINTR || errno == EAGAIN)
1057                                 len = 0;
1058                         else {
1059                                 /*
1060                                  * An error or EOF was encountered.  Put an
1061                                  * error message to stderr buffer.
1062                                  */
1063                                 snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno));
1064                                 buffer_append(&stderr_buffer, buf, strlen(buf));
1065                                 quit_pending = 1;
1066                                 return;
1067                         }
1068                 }
1069                 /* Consume printed data from the buffer. */
1070                 buffer_consume(&stdout_buffer, len);
1071                 stdout_bytes += len;
1072         }
1073         /* Write buffered output to stderr. */
1074         if (FD_ISSET(fileno(stderr), writeset)) {
1075                 /* Write as much data as possible. */
1076                 len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1077                     buffer_len(&stderr_buffer));
1078                 if (len <= 0) {
1079                         if (errno == EINTR || errno == EAGAIN)
1080                                 len = 0;
1081                         else {
1082                                 /* EOF or error, but can't even print error message. */
1083                                 quit_pending = 1;
1084                                 return;
1085                         }
1086                 }
1087                 /* Consume printed characters from the buffer. */
1088                 buffer_consume(&stderr_buffer, len);
1089                 stderr_bytes += len;
1090         }
1091 }
1092
1093 /*
1094  * Get packets from the connection input buffer, and process them as long as
1095  * there are packets available.
1096  *
1097  * Any unknown packets received during the actual
1098  * session cause the session to terminate.  This is
1099  * intended to make debugging easier since no
1100  * confirmations are sent.  Any compatible protocol
1101  * extensions must be negotiated during the
1102  * preparatory phase.
1103  */
1104
1105 static void
1106 client_process_buffered_input_packets(void)
1107 {
1108         dispatch_run(DISPATCH_NONBLOCK, &quit_pending, compat20 ? xxx_kex : NULL);
1109 }
1110
1111 /* scan buf[] for '~' before sending data to the peer */
1112
1113 static int
1114 simple_escape_filter(Channel *c, char *buf, int len)
1115 {
1116         /* XXX we assume c->extended is writeable */
1117         return process_escapes(&c->input, &c->output, &c->extended, buf, len);
1118 }
1119
1120 static void
1121 client_channel_closed(int id, void *arg)
1122 {
1123         channel_cancel_cleanup(id);
1124         session_closed = 1;
1125         leave_raw_mode();
1126 }
1127
1128 /*
1129  * Implements the interactive session with the server.  This is called after
1130  * the user has been authenticated, and a command has been started on the
1131  * remote host.  If escape_char != SSH_ESCAPECHAR_NONE, it is the character
1132  * used as an escape character for terminating or suspending the session.
1133  */
1134
1135 int
1136 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
1137 {
1138         fd_set *readset = NULL, *writeset = NULL;
1139         double start_time, total_time;
1140         int max_fd = 0, max_fd2 = 0, len, rekeying = 0;
1141         u_int nalloc = 0;
1142         char buf[100];
1143
1144         debug("Entering interactive session.");
1145
1146         start_time = get_current_time();
1147
1148         /* Initialize variables. */
1149         escape_pending = 0;
1150         last_was_cr = 1;
1151         exit_status = -1;
1152         stdin_eof = 0;
1153         buffer_high = 64 * 1024;
1154         connection_in = packet_get_connection_in();
1155         connection_out = packet_get_connection_out();
1156         max_fd = MAX(connection_in, connection_out);
1157         if (control_fd != -1)
1158                 max_fd = MAX(max_fd, control_fd);
1159
1160         if (!compat20) {
1161                 /* enable nonblocking unless tty */
1162                 if (!isatty(fileno(stdin)))
1163                         set_nonblock(fileno(stdin));
1164                 if (!isatty(fileno(stdout)))
1165                         set_nonblock(fileno(stdout));
1166                 if (!isatty(fileno(stderr)))
1167                         set_nonblock(fileno(stderr));
1168                 max_fd = MAX(max_fd, fileno(stdin));
1169                 max_fd = MAX(max_fd, fileno(stdout));
1170                 max_fd = MAX(max_fd, fileno(stderr));
1171         }
1172         stdin_bytes = 0;
1173         stdout_bytes = 0;
1174         stderr_bytes = 0;
1175         quit_pending = 0;
1176         escape_char = escape_char_arg;
1177
1178         /* Initialize buffers. */
1179         buffer_init(&stdin_buffer);
1180         buffer_init(&stdout_buffer);
1181         buffer_init(&stderr_buffer);
1182
1183         client_init_dispatch();
1184
1185         /*
1186          * Set signal handlers, (e.g. to restore non-blocking mode)
1187          * but don't overwrite SIG_IGN, matches behaviour from rsh(1)
1188          */
1189         if (signal(SIGHUP, SIG_IGN) != SIG_IGN)
1190                 signal(SIGHUP, signal_handler);
1191         if (signal(SIGINT, SIG_IGN) != SIG_IGN)
1192                 signal(SIGINT, signal_handler);
1193         if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
1194                 signal(SIGQUIT, signal_handler);
1195         if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
1196                 signal(SIGTERM, signal_handler);
1197         signal(SIGWINCH, window_change_handler);
1198
1199         if (have_pty)
1200                 enter_raw_mode();
1201
1202         if (compat20) {
1203                 session_ident = ssh2_chan_id;
1204                 if (escape_char != SSH_ESCAPECHAR_NONE)
1205                         channel_register_filter(session_ident,
1206                             simple_escape_filter);
1207                 if (session_ident != -1)
1208                         channel_register_cleanup(session_ident,
1209                             client_channel_closed);
1210         } else {
1211                 /* Check if we should immediately send eof on stdin. */
1212                 client_check_initial_eof_on_stdin();
1213         }
1214
1215         /* Main loop of the client for the interactive session mode. */
1216         while (!quit_pending) {
1217
1218                 /* Process buffered packets sent by the server. */
1219                 client_process_buffered_input_packets();
1220
1221                 if (compat20 && session_closed && !channel_still_open())
1222                         break;
1223
1224                 rekeying = (xxx_kex != NULL && !xxx_kex->done);
1225
1226                 if (rekeying) {
1227                         debug("rekeying in progress");
1228                 } else {
1229                         /*
1230                          * Make packets of buffered stdin data, and buffer
1231                          * them for sending to the server.
1232                          */
1233                         if (!compat20)
1234                                 client_make_packets_from_stdin_data();
1235
1236                         /*
1237                          * Make packets from buffered channel data, and
1238                          * enqueue them for sending to the server.
1239                          */
1240                         if (packet_not_very_much_data_to_write())
1241                                 channel_output_poll();
1242
1243                         /*
1244                          * Check if the window size has changed, and buffer a
1245                          * message about it to the server if so.
1246                          */
1247                         client_check_window_change();
1248
1249                         if (quit_pending)
1250                                 break;
1251                 }
1252                 /*
1253                  * Wait until we have something to do (something becomes
1254                  * available on one of the descriptors).
1255                  */
1256                 max_fd2 = max_fd;
1257                 client_wait_until_can_do_something(&readset, &writeset,
1258                     &max_fd2, &nalloc, rekeying);
1259
1260                 if (quit_pending)
1261                         break;
1262
1263                 /* Do channel operations unless rekeying in progress. */
1264                 if (!rekeying) {
1265                         channel_after_select(readset, writeset);
1266                         if (need_rekeying || packet_need_rekeying()) {
1267                                 debug("need rekeying");
1268                                 xxx_kex->done = 0;
1269                                 kex_send_kexinit(xxx_kex);
1270                                 need_rekeying = 0;
1271                         }
1272                 }
1273
1274                 /* Buffer input from the connection.  */
1275                 client_process_net_input(readset);
1276
1277                 /* Accept control connections.  */
1278                 client_process_control(readset);
1279
1280                 if (quit_pending)
1281                         break;
1282
1283                 if (!compat20) {
1284                         /* Buffer data from stdin */
1285                         client_process_input(readset);
1286                         /*
1287                          * Process output to stdout and stderr.  Output to
1288                          * the connection is processed elsewhere (above).
1289                          */
1290                         client_process_output(writeset);
1291                 }
1292
1293                 /* Send as much buffered packet data as possible to the sender. */
1294                 if (FD_ISSET(connection_out, writeset))
1295                         packet_write_poll();
1296         }
1297         if (readset)
1298                 xfree(readset);
1299         if (writeset)
1300                 xfree(writeset);
1301
1302         /* Terminate the session. */
1303
1304         /* Stop watching for window change. */
1305         signal(SIGWINCH, SIG_DFL);
1306
1307         channel_free_all();
1308
1309         if (have_pty)
1310                 leave_raw_mode();
1311
1312         /* restore blocking io */
1313         if (!isatty(fileno(stdin)))
1314                 unset_nonblock(fileno(stdin));
1315         if (!isatty(fileno(stdout)))
1316                 unset_nonblock(fileno(stdout));
1317         if (!isatty(fileno(stderr)))
1318                 unset_nonblock(fileno(stderr));
1319
1320         /*
1321          * If there was no shell or command requested, there will be no remote
1322          * exit status to be returned.  In that case, clear error code if the
1323          * connection was deliberately terminated at this end.
1324          */
1325         if (no_shell_flag && received_signal == SIGTERM) {
1326                 received_signal = 0;
1327                 exit_status = 0;
1328         }
1329
1330         if (received_signal)
1331                 fatal("Killed by signal %d.", (int) received_signal);
1332
1333         /*
1334          * In interactive mode (with pseudo tty) display a message indicating
1335          * that the connection has been closed.
1336          */
1337         if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
1338                 snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host);
1339                 buffer_append(&stderr_buffer, buf, strlen(buf));
1340         }
1341
1342         /* Output any buffered data for stdout. */
1343         while (buffer_len(&stdout_buffer) > 0) {
1344                 len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1345                     buffer_len(&stdout_buffer));
1346                 if (len <= 0) {
1347                         error("Write failed flushing stdout buffer.");
1348                         break;
1349                 }
1350                 buffer_consume(&stdout_buffer, len);
1351                 stdout_bytes += len;
1352         }
1353
1354         /* Output any buffered data for stderr. */
1355         while (buffer_len(&stderr_buffer) > 0) {
1356                 len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1357                     buffer_len(&stderr_buffer));
1358                 if (len <= 0) {
1359                         error("Write failed flushing stderr buffer.");
1360                         break;
1361                 }
1362                 buffer_consume(&stderr_buffer, len);
1363                 stderr_bytes += len;
1364         }
1365
1366         /* Clear and free any buffers. */
1367         memset(buf, 0, sizeof(buf));
1368         buffer_free(&stdin_buffer);
1369         buffer_free(&stdout_buffer);
1370         buffer_free(&stderr_buffer);
1371
1372         /* Report bytes transferred, and transfer rates. */
1373         total_time = get_current_time() - start_time;
1374         debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
1375             stdin_bytes, stdout_bytes, stderr_bytes, total_time);
1376         if (total_time > 0)
1377                 debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
1378                     stdin_bytes / total_time, stdout_bytes / total_time,
1379                     stderr_bytes / total_time);
1380
1381         /* Return the exit status of the program. */
1382         debug("Exit status %d", exit_status);
1383         return exit_status;
1384 }
1385
1386 /*********/
1387
1388 static void
1389 client_input_stdout_data(int type, u_int32_t seq, void *ctxt)
1390 {
1391         u_int data_len;
1392         char *data = packet_get_string(&data_len);
1393         packet_check_eom();
1394         buffer_append(&stdout_buffer, data, data_len);
1395         memset(data, 0, data_len);
1396         xfree(data);
1397 }
1398 static void
1399 client_input_stderr_data(int type, u_int32_t seq, void *ctxt)
1400 {
1401         u_int data_len;
1402         char *data = packet_get_string(&data_len);
1403         packet_check_eom();
1404         buffer_append(&stderr_buffer, data, data_len);
1405         memset(data, 0, data_len);
1406         xfree(data);
1407 }
1408 static void
1409 client_input_exit_status(int type, u_int32_t seq, void *ctxt)
1410 {
1411         exit_status = packet_get_int();
1412         packet_check_eom();
1413         /* Acknowledge the exit. */
1414         packet_start(SSH_CMSG_EXIT_CONFIRMATION);
1415         packet_send();
1416         /*
1417          * Must wait for packet to be sent since we are
1418          * exiting the loop.
1419          */
1420         packet_write_wait();
1421         /* Flag that we want to exit. */
1422         quit_pending = 1;
1423 }
1424 static void
1425 client_input_agent_open(int type, u_int32_t seq, void *ctxt)
1426 {
1427         Channel *c = NULL;
1428         int remote_id, sock;
1429
1430         /* Read the remote channel number from the message. */
1431         remote_id = packet_get_int();
1432         packet_check_eom();
1433
1434         /*
1435          * Get a connection to the local authentication agent (this may again
1436          * get forwarded).
1437          */
1438         sock = ssh_get_authentication_socket();
1439
1440         /*
1441          * If we could not connect the agent, send an error message back to
1442          * the server. This should never happen unless the agent dies,
1443          * because authentication forwarding is only enabled if we have an
1444          * agent.
1445          */
1446         if (sock >= 0) {
1447                 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
1448                     -1, 0, 0, 0, "authentication agent connection", 1);
1449                 c->remote_id = remote_id;
1450                 c->force_drain = 1;
1451         }
1452         if (c == NULL) {
1453                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1454                 packet_put_int(remote_id);
1455         } else {
1456                 /* Send a confirmation to the remote host. */
1457                 debug("Forwarding authentication connection.");
1458                 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1459                 packet_put_int(remote_id);
1460                 packet_put_int(c->self);
1461         }
1462         packet_send();
1463 }
1464
1465 static Channel *
1466 client_request_forwarded_tcpip(const char *request_type, int rchan)
1467 {
1468         Channel *c = NULL;
1469         char *listen_address, *originator_address;
1470         int listen_port, originator_port;
1471         int sock;
1472
1473         /* Get rest of the packet */
1474         listen_address = packet_get_string(NULL);
1475         listen_port = packet_get_int();
1476         originator_address = packet_get_string(NULL);
1477         originator_port = packet_get_int();
1478         packet_check_eom();
1479
1480         debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d",
1481             listen_address, listen_port, originator_address, originator_port);
1482
1483         sock = channel_connect_by_listen_address(listen_port);
1484         if (sock < 0) {
1485                 xfree(originator_address);
1486                 xfree(listen_address);
1487                 return NULL;
1488         }
1489         c = channel_new("forwarded-tcpip",
1490             SSH_CHANNEL_CONNECTING, sock, sock, -1,
1491             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
1492             originator_address, 1);
1493         xfree(originator_address);
1494         xfree(listen_address);
1495         return c;
1496 }
1497
1498 static Channel *
1499 client_request_x11(const char *request_type, int rchan)
1500 {
1501         Channel *c = NULL;
1502         char *originator;
1503         int originator_port;
1504         int sock;
1505
1506         if (!options.forward_x11) {
1507                 error("Warning: ssh server tried X11 forwarding.");
1508                 error("Warning: this is probably a break in attempt by a malicious server.");
1509                 return NULL;
1510         }
1511         originator = packet_get_string(NULL);
1512         if (datafellows & SSH_BUG_X11FWD) {
1513                 debug2("buggy server: x11 request w/o originator_port");
1514                 originator_port = 0;
1515         } else {
1516                 originator_port = packet_get_int();
1517         }
1518         packet_check_eom();
1519         /* XXX check permission */
1520         debug("client_request_x11: request from %s %d", originator,
1521             originator_port);
1522         xfree(originator);
1523         sock = x11_connect_display();
1524         if (sock < 0)
1525                 return NULL;
1526         c = channel_new("x11",
1527             SSH_CHANNEL_X11_OPEN, sock, sock, -1,
1528             CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1);
1529         c->force_drain = 1;
1530         return c;
1531 }
1532
1533 static Channel *
1534 client_request_agent(const char *request_type, int rchan)
1535 {
1536         Channel *c = NULL;
1537         int sock;
1538
1539         if (!options.forward_agent) {
1540                 error("Warning: ssh server tried agent forwarding.");
1541                 error("Warning: this is probably a break in attempt by a malicious server.");
1542                 return NULL;
1543         }
1544         sock =  ssh_get_authentication_socket();
1545         if (sock < 0)
1546                 return NULL;
1547         c = channel_new("authentication agent connection",
1548             SSH_CHANNEL_OPEN, sock, sock, -1,
1549             CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
1550             "authentication agent connection", 1);
1551         c->force_drain = 1;
1552         return c;
1553 }
1554
1555 /* XXXX move to generic input handler */
1556 static void
1557 client_input_channel_open(int type, u_int32_t seq, void *ctxt)
1558 {
1559         Channel *c = NULL;
1560         char *ctype;
1561         int rchan;
1562         u_int rmaxpack, rwindow, len;
1563
1564         ctype = packet_get_string(&len);
1565         rchan = packet_get_int();
1566         rwindow = packet_get_int();
1567         rmaxpack = packet_get_int();
1568
1569         debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
1570             ctype, rchan, rwindow, rmaxpack);
1571
1572         if (strcmp(ctype, "forwarded-tcpip") == 0) {
1573                 c = client_request_forwarded_tcpip(ctype, rchan);
1574         } else if (strcmp(ctype, "x11") == 0) {
1575                 c = client_request_x11(ctype, rchan);
1576         } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) {
1577                 c = client_request_agent(ctype, rchan);
1578         }
1579 /* XXX duplicate : */
1580         if (c != NULL) {
1581                 debug("confirm %s", ctype);
1582                 c->remote_id = rchan;
1583                 c->remote_window = rwindow;
1584                 c->remote_maxpacket = rmaxpack;
1585                 if (c->type != SSH_CHANNEL_CONNECTING) {
1586                         packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1587                         packet_put_int(c->remote_id);
1588                         packet_put_int(c->self);
1589                         packet_put_int(c->local_window);
1590                         packet_put_int(c->local_maxpacket);
1591                         packet_send();
1592                 }
1593         } else {
1594                 debug("failure %s", ctype);
1595                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1596                 packet_put_int(rchan);
1597                 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1598                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1599                         packet_put_cstring("open failed");
1600                         packet_put_cstring("");
1601                 }
1602                 packet_send();
1603         }
1604         xfree(ctype);
1605 }
1606 static void
1607 client_input_channel_req(int type, u_int32_t seq, void *ctxt)
1608 {
1609         Channel *c = NULL;
1610         int exitval, id, reply, success = 0;
1611         char *rtype;
1612
1613         id = packet_get_int();
1614         rtype = packet_get_string(NULL);
1615         reply = packet_get_char();
1616
1617         debug("client_input_channel_req: channel %d rtype %s reply %d",
1618             id, rtype, reply);
1619
1620         if (id == -1) {
1621                 error("client_input_channel_req: request for channel -1");
1622         } else if ((c = channel_lookup(id)) == NULL) {
1623                 error("client_input_channel_req: channel %d: unknown channel", id);
1624         } else if (strcmp(rtype, "exit-status") == 0) {
1625                 exitval = packet_get_int();
1626                 if (id == session_ident) {
1627                         success = 1;
1628                         exit_status = exitval;
1629                 } else if (c->ctl_fd == -1) {
1630                         error("client_input_channel_req: unexpected channel %d",
1631                             session_ident);
1632                 } else {
1633                         atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval));
1634                         success = 1;
1635                 }
1636                 packet_check_eom();
1637         }
1638         if (reply) {
1639                 packet_start(success ?
1640                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1641                 packet_put_int(id);
1642                 packet_send();
1643         }
1644         xfree(rtype);
1645 }
1646 static void
1647 client_input_global_request(int type, u_int32_t seq, void *ctxt)
1648 {
1649         char *rtype;
1650         int want_reply;
1651         int success = 0;
1652
1653         rtype = packet_get_string(NULL);
1654         want_reply = packet_get_char();
1655         debug("client_input_global_request: rtype %s want_reply %d",
1656             rtype, want_reply);
1657         if (want_reply) {
1658                 packet_start(success ?
1659                     SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1660                 packet_send();
1661                 packet_write_wait();
1662         }
1663         xfree(rtype);
1664 }
1665
1666 void
1667 client_session2_setup(int id, int want_tty, int want_subsystem,
1668     const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env,
1669     dispatch_fn *subsys_repl)
1670 {
1671         int len;
1672         Channel *c = NULL;
1673
1674         debug2("%s: id %d", __func__, id);
1675
1676         if ((c = channel_lookup(id)) == NULL)
1677                 fatal("client_session2_setup: channel %d: unknown channel", id);
1678
1679         if (want_tty) {
1680                 struct winsize ws;
1681                 struct termios tio;
1682
1683                 /* Store window size in the packet. */
1684                 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0)
1685                         memset(&ws, 0, sizeof(ws));
1686
1687                 channel_request_start(id, "pty-req", 0);
1688                 packet_put_cstring(term != NULL ? term : "");
1689                 packet_put_int(ws.ws_col);
1690                 packet_put_int(ws.ws_row);
1691                 packet_put_int(ws.ws_xpixel);
1692                 packet_put_int(ws.ws_ypixel);
1693                 tio = get_saved_tio();
1694                 tty_make_modes(-1, tiop != NULL ? tiop : &tio);
1695                 packet_send();
1696                 /* XXX wait for reply */
1697                 c->client_tty = 1;
1698         }
1699
1700         /* Transfer any environment variables from client to server */
1701         if (options.num_send_env != 0 && env != NULL) {
1702                 int i, j, matched;
1703                 char *name, *val;
1704
1705                 debug("Sending environment.");
1706                 for (i = 0; env[i] != NULL; i++) {
1707                         /* Split */
1708                         name = xstrdup(env[i]);
1709                         if ((val = strchr(name, '=')) == NULL) {
1710                                 free(name);
1711                                 continue;
1712                         }
1713                         *val++ = '\0';
1714
1715                         matched = 0;
1716                         for (j = 0; j < options.num_send_env; j++) {
1717                                 if (match_pattern(name, options.send_env[j])) {
1718                                         matched = 1;
1719                                         break;
1720                                 }
1721                         }
1722                         if (!matched) {
1723                                 debug3("Ignored env %s", name);
1724                                 free(name);
1725                                 continue;
1726                         }
1727
1728                         debug("Sending env %s = %s", name, val);
1729                         channel_request_start(id, "env", 0);
1730                         packet_put_cstring(name);
1731                         packet_put_cstring(val);
1732                         packet_send();
1733                         free(name);
1734                 }
1735         }
1736
1737         len = buffer_len(cmd);
1738         if (len > 0) {
1739                 if (len > 900)
1740                         len = 900;
1741                 if (want_subsystem) {
1742                         debug("Sending subsystem: %.*s", len, (u_char*)buffer_ptr(cmd));
1743                         channel_request_start(id, "subsystem", subsys_repl != NULL);
1744                         if (subsys_repl != NULL) {
1745                                 /* register callback for reply */
1746                                 /* XXX we assume that client_loop has already been called */
1747                                 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, subsys_repl);
1748                                 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, subsys_repl);
1749                         }
1750                 } else {
1751                         debug("Sending command: %.*s", len, (u_char*)buffer_ptr(cmd));
1752                         channel_request_start(id, "exec", 0);
1753                 }
1754                 packet_put_string(buffer_ptr(cmd), buffer_len(cmd));
1755                 packet_send();
1756         } else {
1757                 channel_request_start(id, "shell", 0);
1758                 packet_send();
1759         }
1760 }
1761
1762 static void
1763 client_init_dispatch_20(void)
1764 {
1765         dispatch_init(&dispatch_protocol_error);
1766
1767         dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1768         dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1769         dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1770         dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1771         dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
1772         dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1773         dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1774         dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
1775         dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1776         dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);
1777
1778         /* rekeying */
1779         dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1780
1781         /* global request reply messages */
1782         dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
1783         dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
1784 }
1785 static void
1786 client_init_dispatch_13(void)
1787 {
1788         dispatch_init(NULL);
1789         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1790         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1791         dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1792         dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1793         dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1794         dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1795         dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
1796         dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
1797         dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);
1798
1799         dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ?
1800             &client_input_agent_open : &deny_input_open);
1801         dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ?
1802             &x11_input_open : &deny_input_open);
1803 }
1804 static void
1805 client_init_dispatch_15(void)
1806 {
1807         client_init_dispatch_13();
1808         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1809         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
1810 }
1811 static void
1812 client_init_dispatch(void)
1813 {
1814         if (compat20)
1815                 client_init_dispatch_20();
1816         else if (compat13)
1817                 client_init_dispatch_13();
1818         else
1819                 client_init_dispatch_15();
1820 }
1821
1822 /* client specific fatal cleanup */
1823 void
1824 cleanup_exit(int i)
1825 {
1826         leave_raw_mode();
1827         leave_non_blocking();
1828         if (options.control_path != NULL && control_fd != -1)
1829                 unlink(options.control_path);
1830         _exit(i);
1831 }