crypto/openssh-3.9p1/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 1.130 2004/08/11 21:43:04 avsm 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         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, allowed;
 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
 604         allowed = 1;
 605         if (options.control_master == 2) {
 606                 char *p, prompt[1024];
 607
 608                 allowed = 0;
 609                 snprintf(prompt, sizeof(prompt),
 610                     "Allow shared connection to %s? ", host);
 611                 p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF);
 612                 if (p != NULL) {
 613                         /*
 614                          * Accept empty responses and responses consisting
 615                          * of the word "yes" as affirmative.
 616                          */
 617                         if (*p == '\0' || *p == '\n' ||
 618                             strcasecmp(p, "yes") == 0)
 619                                 allowed = 1;
 620                         xfree(p);
 621                 }
 622         }
 623
 624         unset_nonblock(client_fd);
 625
 626         buffer_init(&m);
 627
 628         buffer_put_int(&m, allowed);
 629         buffer_put_int(&m, getpid());
 630         if (ssh_msg_send(client_fd, /* version */0, &m) == -1) {
 631                 error("%s: client msg_send failed", __func__);
 632                 close(client_fd);
 633                 buffer_free(&m);
 634                 return;
 635         }
 636         buffer_clear(&m);
 637
 638         if (!allowed) {
 639                 error("Refused control connection");
 640                 close(client_fd);
 641                 buffer_free(&m);
 642                 return;
 643         }
 644
 645         if (ssh_msg_recv(client_fd, &m) == -1) {
 646                 error("%s: client msg_recv failed", __func__);
 647                 close(client_fd);
 648                 buffer_free(&m);
 649                 return;
 650         }
 651
 652         if ((ver = buffer_get_char(&m)) != 0) {
 653                 error("%s: wrong client version %d", __func__, ver);
 654                 buffer_free(&m);
 655                 close(client_fd);
 656                 return;
 657         }
 658
 659         cctx = xmalloc(sizeof(*cctx));
 660         memset(cctx, 0, sizeof(*cctx));
 661
 662         cctx->want_tty = buffer_get_int(&m);
 663         cctx->want_subsys = buffer_get_int(&m);
 664         cctx->term = buffer_get_string(&m, &len);
 665
 666         cmd = buffer_get_string(&m, &len);
 667         buffer_init(&cctx->cmd);
 668         buffer_append(&cctx->cmd, cmd, strlen(cmd));
 669
 670         env_len = buffer_get_int(&m);
 671         env_len = MIN(env_len, 4096);
 672         debug3("%s: receiving %d env vars", __func__, env_len);
 673         if (env_len != 0) {
 674                 cctx->env = xmalloc(sizeof(*cctx->env) * (env_len + 1));
 675                 for (i = 0; i < env_len; i++)
 676                         cctx->env[i] = buffer_get_string(&m, &len);
 677                 cctx->env[i] = NULL;
 678         }
 679
 680         debug2("%s: accepted tty %d, subsys %d, cmd %s", __func__,
 681             cctx->want_tty, cctx->want_subsys, cmd);
 682
 683         /* Gather fds from client */
 684         new_fd[0] = mm_receive_fd(client_fd);
 685         new_fd[1] = mm_receive_fd(client_fd);
 686         new_fd[2] = mm_receive_fd(client_fd);
 687
 688         debug2("%s: got fds stdin %d, stdout %d, stderr %d", __func__,
 689             new_fd[0], new_fd[1], new_fd[2]);
 690
 691         /* Try to pick up ttymodes from client before it goes raw */
 692         if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1)
 693                 error("%s: tcgetattr: %s", __func__, strerror(errno));
 694
 695         buffer_clear(&m);
 696         if (ssh_msg_send(client_fd, /* version */0, &m) == -1) {
 697                 error("%s: client msg_send failed", __func__);
 698                 close(client_fd);
 699                 close(new_fd[0]);
 700                 close(new_fd[1]);
 701                 close(new_fd[2]);
 702                 buffer_free(&m);
 703                 return;
 704         }
 705         buffer_free(&m);
 706
 707         /* enable nonblocking unless tty */
 708         if (!isatty(new_fd[0]))
 709                 set_nonblock(new_fd[0]);
 710         if (!isatty(new_fd[1]))
 711                 set_nonblock(new_fd[1]);
 712         if (!isatty(new_fd[2]))
 713                 set_nonblock(new_fd[2]);
 714
 715         set_nonblock(client_fd);
 716
 717         c = channel_new("session", SSH_CHANNEL_OPENING,
 718             new_fd[0], new_fd[1], new_fd[2],
 719             CHAN_SES_WINDOW_DEFAULT, CHAN_SES_PACKET_DEFAULT,
 720             CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0);
 721
 722         /* XXX */
 723         c->ctl_fd = client_fd;
 724
 725         debug3("%s: channel_new: %d", __func__, c->self);
 726
 727         channel_send_open(c->self);
 728         channel_register_confirm(c->self, client_extra_session2_setup, cctx);
 729 }
 730
 731 static void
 732 process_cmdline(void)
 733 {
 734         void (*handler)(int);
 735         char *s, *cmd;
 736         u_short fwd_port, fwd_host_port;
 737         char buf[1024], sfwd_port[6], sfwd_host_port[6];
 738         int delete = 0;
 739         int local = 0;
 740
 741         leave_raw_mode();
 742         handler = signal(SIGINT, SIG_IGN);
 743         cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
 744         if (s == NULL)
 745                 goto out;
 746         while (*s && isspace(*s))
 747                 s++;
 748         if (*s == '-')
 749                 s++;    /* Skip cmdline '-', if any */
 750         if (*s == '\0')
 751                 goto out;
 752
 753         if (*s == 'h' || *s == 'H' || *s == '?') {
 754                 logit("Commands:");
 755                 logit("      -Lport:host:hostport    Request local forward");
 756                 logit("      -Rport:host:hostport    Request remote forward");
 757                 logit("      -KRhostport             Cancel remote forward");
 758                 goto out;
 759         }
 760
 761         if (*s == 'K') {
 762                 delete = 1;
 763                 s++;
 764         }
 765         if (*s != 'L' && *s != 'R') {
 766                 logit("Invalid command.");
 767                 goto out;
 768         }
 769         if (*s == 'L')
 770                 local = 1;
 771         if (local && delete) {
 772                 logit("Not supported.");
 773                 goto out;
 774         }
 775         if ((!local || delete) && !compat20) {
 776                 logit("Not supported for SSH protocol version 1.");
 777                 goto out;
 778         }
 779
 780         s++;
 781         while (*s && isspace(*s))
 782                 s++;
 783
 784         if (delete) {
 785                 if (sscanf(s, "%5[0-9]", sfwd_host_port) != 1) {
 786                         logit("Bad forwarding specification.");
 787                         goto out;
 788                 }
 789                 if ((fwd_host_port = a2port(sfwd_host_port)) == 0) {
 790                         logit("Bad forwarding port(s).");
 791                         goto out;
 792                 }
 793                 channel_request_rforward_cancel(fwd_host_port);
 794         } else {
 795                 if (sscanf(s, "%5[0-9]:%255[^:]:%5[0-9]",
 796                     sfwd_port, buf, sfwd_host_port) != 3 &&
 797                     sscanf(s, "%5[0-9]/%255[^/]/%5[0-9]",
 798                     sfwd_port, buf, sfwd_host_port) != 3) {
 799                         logit("Bad forwarding specification.");
 800                         goto out;
 801                 }
 802                 if ((fwd_port = a2port(sfwd_port)) == 0 ||
 803                     (fwd_host_port = a2port(sfwd_host_port)) == 0) {
 804                         logit("Bad forwarding port(s).");
 805                         goto out;
 806                 }
 807                 if (local) {
 808                         if (channel_setup_local_fwd_listener(fwd_port, buf,
 809                             fwd_host_port, options.gateway_ports) < 0) {
 810                                 logit("Port forwarding failed.");
 811                                 goto out;
 812                         }
 813                 } else
 814                         channel_request_remote_forwarding(fwd_port, buf,
 815                             fwd_host_port);
 816                 logit("Forwarding port.");
 817         }
 818
 819 out:
 820         signal(SIGINT, handler);
 821         enter_raw_mode();
 822         if (cmd)
 823                 xfree(cmd);
 824 }
 825
 826 /* process the characters one by one */
 827 static int
 828 process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
 829 {
 830         char string[1024];
 831         pid_t pid;
 832         int bytes = 0;
 833         u_int i;
 834         u_char ch;
 835         char *s;
 836
 837         for (i = 0; i < len; i++) {
 838                 /* Get one character at a time. */
 839                 ch = buf[i];
 840
 841                 if (escape_pending) {
 842                         /* We have previously seen an escape character. */
 843                         /* Clear the flag now. */
 844                         escape_pending = 0;
 845
 846                         /* Process the escaped character. */
 847                         switch (ch) {
 848                         case '.':
 849                                 /* Terminate the connection. */
 850                                 snprintf(string, sizeof string, "%c.\r\n", escape_char);
 851                                 buffer_append(berr, string, strlen(string));
 852
 853                                 quit_pending = 1;
 854                                 return -1;
 855
 856                         case 'Z' - 64:
 857                                 /* Suspend the program. */
 858                                 /* Print a message to that effect to the user. */
 859                                 snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char);
 860                                 buffer_append(berr, string, strlen(string));
 861
 862                                 /* Restore terminal modes and suspend. */
 863                                 client_suspend_self(bin, bout, berr);
 864
 865                                 /* We have been continued. */
 866                                 continue;
 867
 868                         case 'B':
 869                                 if (compat20) {
 870                                         snprintf(string, sizeof string,
 871                                             "%cB\r\n", escape_char);
 872                                         buffer_append(berr, string,
 873                                             strlen(string));
 874                                         channel_request_start(session_ident,
 875                                             "break", 0);
 876                                         packet_put_int(1000);
 877                                         packet_send();
 878                                 }
 879                                 continue;
 880
 881                         case 'R':
 882                                 if (compat20) {
 883                                         if (datafellows & SSH_BUG_NOREKEY)
 884                                                 logit("Server does not support re-keying");
 885                                         else
 886                                                 need_rekeying = 1;
 887                                 }
 888                                 continue;
 889
 890                         case '&':
 891                                 /*
 892                                  * Detach the program (continue to serve connections,
 893                                  * but put in background and no more new connections).
 894                                  */
 895                                 /* Restore tty modes. */
 896                                 leave_raw_mode();
 897
 898                                 /* Stop listening for new connections. */
 899                                 channel_stop_listening();
 900
 901                                 snprintf(string, sizeof string,
 902                                     "%c& [backgrounded]\n", escape_char);
 903                                 buffer_append(berr, string, strlen(string));
 904
 905                                 /* Fork into background. */
 906                                 pid = fork();
 907                                 if (pid < 0) {
 908                                         error("fork: %.100s", strerror(errno));
 909                                         continue;
 910                                 }
 911                                 if (pid != 0) { /* This is the parent. */
 912                                         /* The parent just exits. */
 913                                         exit(0);
 914                                 }
 915                                 /* The child continues serving connections. */
 916                                 if (compat20) {
 917                                         buffer_append(bin, "\004", 1);
 918                                         /* fake EOF on stdin */
 919                                         return -1;
 920                                 } else if (!stdin_eof) {
 921                                         /*
 922                                          * Sending SSH_CMSG_EOF alone does not always appear
 923                                          * to be enough.  So we try to send an EOF character
 924                                          * first.
 925                                          */
 926                                         packet_start(SSH_CMSG_STDIN_DATA);
 927                                         packet_put_string("\004", 1);
 928                                         packet_send();
 929                                         /* Close stdin. */
 930                                         stdin_eof = 1;
 931                                         if (buffer_len(bin) == 0) {
 932                                                 packet_start(SSH_CMSG_EOF);
 933                                                 packet_send();
 934                                         }
 935                                 }
 936                                 continue;
 937
 938                         case '?':
 939                                 snprintf(string, sizeof string,
 940 "%c?\r\n\
 941 Supported escape sequences:\r\n\
 942 %c.  - terminate connection\r\n\
 943 %cB  - send a BREAK to the remote system\r\n\
 944 %cC  - open a command line\r\n\
 945 %cR  - Request rekey (SSH protocol 2 only)\r\n\
 946 %c^Z - suspend ssh\r\n\
 947 %c#  - list forwarded connections\r\n\
 948 %c&  - background ssh (when waiting for connections to terminate)\r\n\
 949 %c?  - this message\r\n\
 950 %c%c  - send the escape character by typing it twice\r\n\
 951 (Note that escapes are only recognized immediately after newline.)\r\n",
 952                                     escape_char, escape_char, escape_char, escape_char,
 953                                     escape_char, escape_char, escape_char, escape_char,
 954                                     escape_char, escape_char, escape_char);
 955                                 buffer_append(berr, string, strlen(string));
 956                                 continue;
 957
 958                         case '#':
 959                                 snprintf(string, sizeof string, "%c#\r\n", escape_char);
 960                                 buffer_append(berr, string, strlen(string));
 961                                 s = channel_open_message();
 962                                 buffer_append(berr, s, strlen(s));
 963                                 xfree(s);
 964                                 continue;
 965
 966                         case 'C':
 967                                 process_cmdline();
 968                                 continue;
 969
 970                         default:
 971                                 if (ch != escape_char) {
 972                                         buffer_put_char(bin, escape_char);
 973                                         bytes++;
 974                                 }
 975                                 /* Escaped characters fall through here */
 976                                 break;
 977                         }
 978                 } else {
 979                         /*
 980                          * The previous character was not an escape char. Check if this
 981                          * is an escape.
 982                          */
 983                         if (last_was_cr && ch == escape_char) {
 984                                 /* It is. Set the flag and continue to next character. */
 985                                 escape_pending = 1;
 986                                 continue;
 987                         }
 988                 }
 989
 990                 /*
 991                  * Normal character.  Record whether it was a newline,
 992                  * and append it to the buffer.
 993                  */
 994                 last_was_cr = (ch == '\r' || ch == '\n');
 995                 buffer_put_char(bin, ch);
 996                 bytes++;
 997         }
 998         return bytes;
 999 }
1000
1001 static void
1002 client_process_input(fd_set * readset)
1003 {
1004         int len;
1005         char buf[8192];
1006
1007         /* Read input from stdin. */
1008         if (FD_ISSET(fileno(stdin), readset)) {
1009                 /* Read as much as possible. */
1010                 len = read(fileno(stdin), buf, sizeof(buf));
1011                 if (len < 0 && (errno == EAGAIN || errno == EINTR))
1012                         return;         /* we'll try again later */
1013                 if (len <= 0) {
1014                         /*
1015                          * Received EOF or error.  They are treated
1016                          * similarly, except that an error message is printed
1017                          * if it was an error condition.
1018                          */
1019                         if (len < 0) {
1020                                 snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno));
1021                                 buffer_append(&stderr_buffer, buf, strlen(buf));
1022                         }
1023                         /* Mark that we have seen EOF. */
1024                         stdin_eof = 1;
1025                         /*
1026                          * Send an EOF message to the server unless there is
1027                          * data in the buffer.  If there is data in the
1028                          * buffer, no message will be sent now.  Code
1029                          * elsewhere will send the EOF when the buffer
1030                          * becomes empty if stdin_eof is set.
1031                          */
1032                         if (buffer_len(&stdin_buffer) == 0) {
1033                                 packet_start(SSH_CMSG_EOF);
1034                                 packet_send();
1035                         }
1036                 } else if (escape_char == SSH_ESCAPECHAR_NONE) {
1037                         /*
1038                          * Normal successful read, and no escape character.
1039                          * Just append the data to buffer.
1040                          */
1041                         buffer_append(&stdin_buffer, buf, len);
1042                 } else {
1043                         /*
1044                          * Normal, successful read.  But we have an escape character
1045                          * and have to process the characters one by one.
1046                          */
1047                         if (process_escapes(&stdin_buffer, &stdout_buffer,
1048                             &stderr_buffer, buf, len) == -1)
1049                                 return;
1050                 }
1051         }
1052 }
1053
1054 static void
1055 client_process_output(fd_set * writeset)
1056 {
1057         int len;
1058         char buf[100];
1059
1060         /* Write buffered output to stdout. */
1061         if (FD_ISSET(fileno(stdout), writeset)) {
1062                 /* Write as much data as possible. */
1063                 len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1064                     buffer_len(&stdout_buffer));
1065                 if (len <= 0) {
1066                         if (errno == EINTR || errno == EAGAIN)
1067                                 len = 0;
1068                         else {
1069                                 /*
1070                                  * An error or EOF was encountered.  Put an
1071                                  * error message to stderr buffer.
1072                                  */
1073                                 snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno));
1074                                 buffer_append(&stderr_buffer, buf, strlen(buf));
1075                                 quit_pending = 1;
1076                                 return;
1077                         }
1078                 }
1079                 /* Consume printed data from the buffer. */
1080                 buffer_consume(&stdout_buffer, len);
1081                 stdout_bytes += len;
1082         }
1083         /* Write buffered output to stderr. */
1084         if (FD_ISSET(fileno(stderr), writeset)) {
1085                 /* Write as much data as possible. */
1086                 len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1087                     buffer_len(&stderr_buffer));
1088                 if (len <= 0) {
1089                         if (errno == EINTR || errno == EAGAIN)
1090                                 len = 0;
1091                         else {
1092                                 /* EOF or error, but can't even print error message. */
1093                                 quit_pending = 1;
1094                                 return;
1095                         }
1096                 }
1097                 /* Consume printed characters from the buffer. */
1098                 buffer_consume(&stderr_buffer, len);
1099                 stderr_bytes += len;
1100         }
1101 }
1102
1103 /*
1104  * Get packets from the connection input buffer, and process them as long as
1105  * there are packets available.
1106  *
1107  * Any unknown packets received during the actual
1108  * session cause the session to terminate.  This is
1109  * intended to make debugging easier since no
1110  * confirmations are sent.  Any compatible protocol
1111  * extensions must be negotiated during the
1112  * preparatory phase.
1113  */
1114
1115 static void
1116 client_process_buffered_input_packets(void)
1117 {
1118         dispatch_run(DISPATCH_NONBLOCK, &quit_pending, compat20 ? xxx_kex : NULL);
1119 }
1120
1121 /* scan buf[] for '~' before sending data to the peer */
1122
1123 static int
1124 simple_escape_filter(Channel *c, char *buf, int len)
1125 {
1126         /* XXX we assume c->extended is writeable */
1127         return process_escapes(&c->input, &c->output, &c->extended, buf, len);
1128 }
1129
1130 static void
1131 client_channel_closed(int id, void *arg)
1132 {
1133         channel_cancel_cleanup(id);
1134         session_closed = 1;
1135         leave_raw_mode();
1136 }
1137
1138 /*
1139  * Implements the interactive session with the server.  This is called after
1140  * the user has been authenticated, and a command has been started on the
1141  * remote host.  If escape_char != SSH_ESCAPECHAR_NONE, it is the character
1142  * used as an escape character for terminating or suspending the session.
1143  */
1144
1145 int
1146 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
1147 {
1148         fd_set *readset = NULL, *writeset = NULL;
1149         double start_time, total_time;
1150         int max_fd = 0, max_fd2 = 0, len, rekeying = 0;
1151         u_int nalloc = 0;
1152         char buf[100];
1153
1154         debug("Entering interactive session.");
1155
1156         start_time = get_current_time();
1157
1158         /* Initialize variables. */
1159         escape_pending = 0;
1160         last_was_cr = 1;
1161         exit_status = -1;
1162         stdin_eof = 0;
1163         buffer_high = 64 * 1024;
1164         connection_in = packet_get_connection_in();
1165         connection_out = packet_get_connection_out();
1166         max_fd = MAX(connection_in, connection_out);
1167         if (control_fd != -1)
1168                 max_fd = MAX(max_fd, control_fd);
1169
1170         if (!compat20) {
1171                 /* enable nonblocking unless tty */
1172                 if (!isatty(fileno(stdin)))
1173                         set_nonblock(fileno(stdin));
1174                 if (!isatty(fileno(stdout)))
1175                         set_nonblock(fileno(stdout));
1176                 if (!isatty(fileno(stderr)))
1177                         set_nonblock(fileno(stderr));
1178                 max_fd = MAX(max_fd, fileno(stdin));
1179                 max_fd = MAX(max_fd, fileno(stdout));
1180                 max_fd = MAX(max_fd, fileno(stderr));
1181         }
1182         stdin_bytes = 0;
1183         stdout_bytes = 0;
1184         stderr_bytes = 0;
1185         quit_pending = 0;
1186         escape_char = escape_char_arg;
1187
1188         /* Initialize buffers. */
1189         buffer_init(&stdin_buffer);
1190         buffer_init(&stdout_buffer);
1191         buffer_init(&stderr_buffer);
1192
1193         client_init_dispatch();
1194
1195         /*
1196          * Set signal handlers, (e.g. to restore non-blocking mode)
1197          * but don't overwrite SIG_IGN, matches behaviour from rsh(1)
1198          */
1199         if (signal(SIGINT, SIG_IGN) != SIG_IGN)
1200                 signal(SIGINT, signal_handler);
1201         if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
1202                 signal(SIGQUIT, signal_handler);
1203         if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
1204                 signal(SIGTERM, signal_handler);
1205         if (have_pty)
1206                 signal(SIGWINCH, window_change_handler);
1207
1208         if (have_pty)
1209                 enter_raw_mode();
1210
1211         if (compat20) {
1212                 session_ident = ssh2_chan_id;
1213                 if (escape_char != SSH_ESCAPECHAR_NONE)
1214                         channel_register_filter(session_ident,
1215                             simple_escape_filter);
1216                 if (session_ident != -1)
1217                         channel_register_cleanup(session_ident,
1218                             client_channel_closed);
1219         } else {
1220                 /* Check if we should immediately send eof on stdin. */
1221                 client_check_initial_eof_on_stdin();
1222         }
1223
1224         /* Main loop of the client for the interactive session mode. */
1225         while (!quit_pending) {
1226
1227                 /* Process buffered packets sent by the server. */
1228                 client_process_buffered_input_packets();
1229
1230                 if (compat20 && session_closed && !channel_still_open())
1231                         break;
1232
1233                 rekeying = (xxx_kex != NULL && !xxx_kex->done);
1234
1235                 if (rekeying) {
1236                         debug("rekeying in progress");
1237                 } else {
1238                         /*
1239                          * Make packets of buffered stdin data, and buffer
1240                          * them for sending to the server.
1241                          */
1242                         if (!compat20)
1243                                 client_make_packets_from_stdin_data();
1244
1245                         /*
1246                          * Make packets from buffered channel data, and
1247                          * enqueue them for sending to the server.
1248                          */
1249                         if (packet_not_very_much_data_to_write())
1250                                 channel_output_poll();
1251
1252                         /*
1253                          * Check if the window size has changed, and buffer a
1254                          * message about it to the server if so.
1255                          */
1256                         client_check_window_change();
1257
1258                         if (quit_pending)
1259                                 break;
1260                 }
1261                 /*
1262                  * Wait until we have something to do (something becomes
1263                  * available on one of the descriptors).
1264                  */
1265                 max_fd2 = max_fd;
1266                 client_wait_until_can_do_something(&readset, &writeset,
1267                     &max_fd2, &nalloc, rekeying);
1268
1269                 if (quit_pending)
1270                         break;
1271
1272                 /* Do channel operations unless rekeying in progress. */
1273                 if (!rekeying) {
1274                         channel_after_select(readset, writeset);
1275                         if (need_rekeying || packet_need_rekeying()) {
1276                                 debug("need rekeying");
1277                                 xxx_kex->done = 0;
1278                                 kex_send_kexinit(xxx_kex);
1279                                 need_rekeying = 0;
1280                         }
1281                 }
1282
1283                 /* Buffer input from the connection.  */
1284                 client_process_net_input(readset);
1285
1286                 /* Accept control connections.  */
1287                 client_process_control(readset);
1288
1289                 if (quit_pending)
1290                         break;
1291
1292                 if (!compat20) {
1293                         /* Buffer data from stdin */
1294                         client_process_input(readset);
1295                         /*
1296                          * Process output to stdout and stderr.  Output to
1297                          * the connection is processed elsewhere (above).
1298                          */
1299                         client_process_output(writeset);
1300                 }
1301
1302                 /* Send as much buffered packet data as possible to the sender. */
1303                 if (FD_ISSET(connection_out, writeset))
1304                         packet_write_poll();
1305         }
1306         if (readset)
1307                 xfree(readset);
1308         if (writeset)
1309                 xfree(writeset);
1310
1311         /* Terminate the session. */
1312
1313         /* Stop watching for window change. */
1314         if (have_pty)
1315                 signal(SIGWINCH, SIG_DFL);
1316
1317         channel_free_all();
1318
1319         if (have_pty)
1320                 leave_raw_mode();
1321
1322         /* restore blocking io */
1323         if (!isatty(fileno(stdin)))
1324                 unset_nonblock(fileno(stdin));
1325         if (!isatty(fileno(stdout)))
1326                 unset_nonblock(fileno(stdout));
1327         if (!isatty(fileno(stderr)))
1328                 unset_nonblock(fileno(stderr));
1329
1330         /*
1331          * If there was no shell or command requested, there will be no remote
1332          * exit status to be returned.  In that case, clear error code if the
1333          * connection was deliberately terminated at this end.
1334          */
1335         if (no_shell_flag && received_signal == SIGTERM) {
1336                 received_signal = 0;
1337                 exit_status = 0;
1338         }
1339
1340         if (received_signal)
1341                 fatal("Killed by signal %d.", (int) received_signal);
1342
1343         /*
1344          * In interactive mode (with pseudo tty) display a message indicating
1345          * that the connection has been closed.
1346          */
1347         if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
1348                 snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host);
1349                 buffer_append(&stderr_buffer, buf, strlen(buf));
1350         }
1351
1352         /* Output any buffered data for stdout. */
1353         while (buffer_len(&stdout_buffer) > 0) {
1354                 len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1355                     buffer_len(&stdout_buffer));
1356                 if (len <= 0) {
1357                         error("Write failed flushing stdout buffer.");
1358                         break;
1359                 }
1360                 buffer_consume(&stdout_buffer, len);
1361                 stdout_bytes += len;
1362         }
1363
1364         /* Output any buffered data for stderr. */
1365         while (buffer_len(&stderr_buffer) > 0) {
1366                 len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1367                     buffer_len(&stderr_buffer));
1368                 if (len <= 0) {
1369                         error("Write failed flushing stderr buffer.");
1370                         break;
1371                 }
1372                 buffer_consume(&stderr_buffer, len);
1373                 stderr_bytes += len;
1374         }
1375
1376         /* Clear and free any buffers. */
1377         memset(buf, 0, sizeof(buf));
1378         buffer_free(&stdin_buffer);
1379         buffer_free(&stdout_buffer);
1380         buffer_free(&stderr_buffer);
1381
1382         /* Report bytes transferred, and transfer rates. */
1383         total_time = get_current_time() - start_time;
1384         debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
1385             stdin_bytes, stdout_bytes, stderr_bytes, total_time);
1386         if (total_time > 0)
1387                 debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
1388                     stdin_bytes / total_time, stdout_bytes / total_time,
1389                     stderr_bytes / total_time);
1390
1391         /* Return the exit status of the program. */
1392         debug("Exit status %d", exit_status);
1393         return exit_status;
1394 }
1395
1396 /*********/
1397
1398 static void
1399 client_input_stdout_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(&stdout_buffer, data, data_len);
1405         memset(data, 0, data_len);
1406         xfree(data);
1407 }
1408 static void
1409 client_input_stderr_data(int type, u_int32_t seq, void *ctxt)
1410 {
1411         u_int data_len;
1412         char *data = packet_get_string(&data_len);
1413         packet_check_eom();
1414         buffer_append(&stderr_buffer, data, data_len);
1415         memset(data, 0, data_len);
1416         xfree(data);
1417 }
1418 static void
1419 client_input_exit_status(int type, u_int32_t seq, void *ctxt)
1420 {
1421         exit_status = packet_get_int();
1422         packet_check_eom();
1423         /* Acknowledge the exit. */
1424         packet_start(SSH_CMSG_EXIT_CONFIRMATION);
1425         packet_send();
1426         /*
1427          * Must wait for packet to be sent since we are
1428          * exiting the loop.
1429          */
1430         packet_write_wait();
1431         /* Flag that we want to exit. */
1432         quit_pending = 1;
1433 }
1434 static void
1435 client_input_agent_open(int type, u_int32_t seq, void *ctxt)
1436 {
1437         Channel *c = NULL;
1438         int remote_id, sock;
1439
1440         /* Read the remote channel number from the message. */
1441         remote_id = packet_get_int();
1442         packet_check_eom();
1443
1444         /*
1445          * Get a connection to the local authentication agent (this may again
1446          * get forwarded).
1447          */
1448         sock = ssh_get_authentication_socket();
1449
1450         /*
1451          * If we could not connect the agent, send an error message back to
1452          * the server. This should never happen unless the agent dies,
1453          * because authentication forwarding is only enabled if we have an
1454          * agent.
1455          */
1456         if (sock >= 0) {
1457                 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
1458                     -1, 0, 0, 0, "authentication agent connection", 1);
1459                 c->remote_id = remote_id;
1460                 c->force_drain = 1;
1461         }
1462         if (c == NULL) {
1463                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1464                 packet_put_int(remote_id);
1465         } else {
1466                 /* Send a confirmation to the remote host. */
1467                 debug("Forwarding authentication connection.");
1468                 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1469                 packet_put_int(remote_id);
1470                 packet_put_int(c->self);
1471         }
1472         packet_send();
1473 }
1474
1475 static Channel *
1476 client_request_forwarded_tcpip(const char *request_type, int rchan)
1477 {
1478         Channel *c = NULL;
1479         char *listen_address, *originator_address;
1480         int listen_port, originator_port;
1481         int sock;
1482
1483         /* Get rest of the packet */
1484         listen_address = packet_get_string(NULL);
1485         listen_port = packet_get_int();
1486         originator_address = packet_get_string(NULL);
1487         originator_port = packet_get_int();
1488         packet_check_eom();
1489
1490         debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d",
1491             listen_address, listen_port, originator_address, originator_port);
1492
1493         sock = channel_connect_by_listen_address(listen_port);
1494         if (sock < 0) {
1495                 xfree(originator_address);
1496                 xfree(listen_address);
1497                 return NULL;
1498         }
1499         c = channel_new("forwarded-tcpip",
1500             SSH_CHANNEL_CONNECTING, sock, sock, -1,
1501             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
1502             originator_address, 1);
1503         xfree(originator_address);
1504         xfree(listen_address);
1505         return c;
1506 }
1507
1508 static Channel *
1509 client_request_x11(const char *request_type, int rchan)
1510 {
1511         Channel *c = NULL;
1512         char *originator;
1513         int originator_port;
1514         int sock;
1515
1516         if (!options.forward_x11) {
1517                 error("Warning: ssh server tried X11 forwarding.");
1518                 error("Warning: this is probably a break in attempt by a malicious server.");
1519                 return NULL;
1520         }
1521         originator = packet_get_string(NULL);
1522         if (datafellows & SSH_BUG_X11FWD) {
1523                 debug2("buggy server: x11 request w/o originator_port");
1524                 originator_port = 0;
1525         } else {
1526                 originator_port = packet_get_int();
1527         }
1528         packet_check_eom();
1529         /* XXX check permission */
1530         debug("client_request_x11: request from %s %d", originator,
1531             originator_port);
1532         xfree(originator);
1533         sock = x11_connect_display();
1534         if (sock < 0)
1535                 return NULL;
1536         c = channel_new("x11",
1537             SSH_CHANNEL_X11_OPEN, sock, sock, -1,
1538             CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1);
1539         c->force_drain = 1;
1540         return c;
1541 }
1542
1543 static Channel *
1544 client_request_agent(const char *request_type, int rchan)
1545 {
1546         Channel *c = NULL;
1547         int sock;
1548
1549         if (!options.forward_agent) {
1550                 error("Warning: ssh server tried agent forwarding.");
1551                 error("Warning: this is probably a break in attempt by a malicious server.");
1552                 return NULL;
1553         }
1554         sock =  ssh_get_authentication_socket();
1555         if (sock < 0)
1556                 return NULL;
1557         c = channel_new("authentication agent connection",
1558             SSH_CHANNEL_OPEN, sock, sock, -1,
1559             CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
1560             "authentication agent connection", 1);
1561         c->force_drain = 1;
1562         return c;
1563 }
1564
1565 /* XXXX move to generic input handler */
1566 static void
1567 client_input_channel_open(int type, u_int32_t seq, void *ctxt)
1568 {
1569         Channel *c = NULL;
1570         char *ctype;
1571         int rchan;
1572         u_int rmaxpack, rwindow, len;
1573
1574         ctype = packet_get_string(&len);
1575         rchan = packet_get_int();
1576         rwindow = packet_get_int();
1577         rmaxpack = packet_get_int();
1578
1579         debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
1580             ctype, rchan, rwindow, rmaxpack);
1581
1582         if (strcmp(ctype, "forwarded-tcpip") == 0) {
1583                 c = client_request_forwarded_tcpip(ctype, rchan);
1584         } else if (strcmp(ctype, "x11") == 0) {
1585                 c = client_request_x11(ctype, rchan);
1586         } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) {
1587                 c = client_request_agent(ctype, rchan);
1588         }
1589 /* XXX duplicate : */
1590         if (c != NULL) {
1591                 debug("confirm %s", ctype);
1592                 c->remote_id = rchan;
1593                 c->remote_window = rwindow;
1594                 c->remote_maxpacket = rmaxpack;
1595                 if (c->type != SSH_CHANNEL_CONNECTING) {
1596                         packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1597                         packet_put_int(c->remote_id);
1598                         packet_put_int(c->self);
1599                         packet_put_int(c->local_window);
1600                         packet_put_int(c->local_maxpacket);
1601                         packet_send();
1602                 }
1603         } else {
1604                 debug("failure %s", ctype);
1605                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1606                 packet_put_int(rchan);
1607                 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1608                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1609                         packet_put_cstring("open failed");
1610                         packet_put_cstring("");
1611                 }
1612                 packet_send();
1613         }
1614         xfree(ctype);
1615 }
1616 static void
1617 client_input_channel_req(int type, u_int32_t seq, void *ctxt)
1618 {
1619         Channel *c = NULL;
1620         int exitval, id, reply, success = 0;
1621         char *rtype;
1622
1623         id = packet_get_int();
1624         rtype = packet_get_string(NULL);
1625         reply = packet_get_char();
1626
1627         debug("client_input_channel_req: channel %d rtype %s reply %d",
1628             id, rtype, reply);
1629
1630         if (id == -1) {
1631                 error("client_input_channel_req: request for channel -1");
1632         } else if ((c = channel_lookup(id)) == NULL) {
1633                 error("client_input_channel_req: channel %d: unknown channel", id);
1634         } else if (strcmp(rtype, "exit-status") == 0) {
1635                 exitval = packet_get_int();
1636                 if (id == session_ident) {
1637                         success = 1;
1638                         exit_status = exitval;
1639                 } else if (c->ctl_fd == -1) {
1640                         error("client_input_channel_req: unexpected channel %d",
1641                             session_ident);
1642                 } else {
1643                         atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval));
1644                         success = 1;
1645                 }
1646                 packet_check_eom();
1647         }
1648         if (reply) {
1649                 packet_start(success ?
1650                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1651                 packet_put_int(id);
1652                 packet_send();
1653         }
1654         xfree(rtype);
1655 }
1656 static void
1657 client_input_global_request(int type, u_int32_t seq, void *ctxt)
1658 {
1659         char *rtype;
1660         int want_reply;
1661         int success = 0;
1662
1663         rtype = packet_get_string(NULL);
1664         want_reply = packet_get_char();
1665         debug("client_input_global_request: rtype %s want_reply %d",
1666             rtype, want_reply);
1667         if (want_reply) {
1668                 packet_start(success ?
1669                     SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1670                 packet_send();
1671                 packet_write_wait();
1672         }
1673         xfree(rtype);
1674 }
1675
1676 void
1677 client_session2_setup(int id, int want_tty, int want_subsystem,
1678     const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env,
1679     dispatch_fn *subsys_repl)
1680 {
1681         int len;
1682
1683         debug2("%s: id %d", __func__, id);
1684
1685         if (want_tty) {
1686                 struct winsize ws;
1687                 struct termios tio;
1688
1689                 /* Store window size in the packet. */
1690                 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0)
1691                         memset(&ws, 0, sizeof(ws));
1692
1693                 channel_request_start(id, "pty-req", 0);
1694                 packet_put_cstring(term != NULL ? term : "");
1695                 packet_put_int(ws.ws_col);
1696                 packet_put_int(ws.ws_row);
1697                 packet_put_int(ws.ws_xpixel);
1698                 packet_put_int(ws.ws_ypixel);
1699                 tio = get_saved_tio();
1700                 tty_make_modes(-1, tiop != NULL ? tiop : &tio);
1701                 packet_send();
1702                 /* XXX wait for reply */
1703         }
1704
1705         /* Transfer any environment variables from client to server */
1706         if (options.num_send_env != 0 && env != NULL) {
1707                 int i, j, matched;
1708                 char *name, *val;
1709
1710                 debug("Sending environment.");
1711                 for (i = 0; env[i] != NULL; i++) {
1712                         /* Split */
1713                         name = xstrdup(env[i]);
1714                         if ((val = strchr(name, '=')) == NULL) {
1715                                 free(name);
1716                                 continue;
1717                         }
1718                         *val++ = '\0';
1719
1720                         matched = 0;
1721                         for (j = 0; j < options.num_send_env; j++) {
1722                                 if (match_pattern(name, options.send_env[j])) {
1723                                         matched = 1;
1724                                         break;
1725                                 }
1726                         }
1727                         if (!matched) {
1728                                 debug3("Ignored env %s", name);
1729                                 free(name);
1730                                 continue;
1731                         }
1732
1733                         debug("Sending env %s = %s", name, val);
1734                         channel_request_start(id, "env", 0);
1735                         packet_put_cstring(name);
1736                         packet_put_cstring(val);
1737                         packet_send();
1738                         free(name);
1739                 }
1740         }
1741
1742         len = buffer_len(cmd);
1743         if (len > 0) {
1744                 if (len > 900)
1745                         len = 900;
1746                 if (want_subsystem) {
1747                         debug("Sending subsystem: %.*s", len, (u_char*)buffer_ptr(cmd));
1748                         channel_request_start(id, "subsystem", subsys_repl != NULL);
1749                         if (subsys_repl != NULL) {
1750                                 /* register callback for reply */
1751                                 /* XXX we assume that client_loop has already been called */
1752                                 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, subsys_repl);
1753                                 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, subsys_repl);
1754                         }
1755                 } else {
1756                         debug("Sending command: %.*s", len, (u_char*)buffer_ptr(cmd));
1757                         channel_request_start(id, "exec", 0);
1758                 }
1759                 packet_put_string(buffer_ptr(cmd), buffer_len(cmd));
1760                 packet_send();
1761         } else {
1762                 channel_request_start(id, "shell", 0);
1763                 packet_send();
1764         }
1765 }
1766
1767 static void
1768 client_init_dispatch_20(void)
1769 {
1770         dispatch_init(&dispatch_protocol_error);
1771
1772         dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1773         dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1774         dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1775         dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1776         dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
1777         dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1778         dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1779         dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
1780         dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1781         dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);
1782
1783         /* rekeying */
1784         dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1785
1786         /* global request reply messages */
1787         dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
1788         dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
1789 }
1790 static void
1791 client_init_dispatch_13(void)
1792 {
1793         dispatch_init(NULL);
1794         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1795         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1796         dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1797         dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1798         dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1799         dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1800         dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
1801         dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
1802         dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);
1803
1804         dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ?
1805             &client_input_agent_open : &deny_input_open);
1806         dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ?
1807             &x11_input_open : &deny_input_open);
1808 }
1809 static void
1810 client_init_dispatch_15(void)
1811 {
1812         client_init_dispatch_13();
1813         dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1814         dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
1815 }
1816 static void
1817 client_init_dispatch(void)
1818 {
1819         if (compat20)
1820                 client_init_dispatch_20();
1821         else if (compat13)
1822                 client_init_dispatch_13();
1823         else
1824                 client_init_dispatch_15();
1825 }
1826
1827 /* client specific fatal cleanup */
1828 void
1829 cleanup_exit(int i)
1830 {
1831         leave_raw_mode();
1832         leave_non_blocking();
1833         if (options.control_path != NULL && control_fd != -1)
1834                 unlink(options.control_path);
1835         _exit(i);
1836 }