crypto/openssh/clientloop.c

   1 /* $OpenBSD: clientloop.c,v 1.305 2017/09/19 04:24:22 djm Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * The main loop for the interactive session (client side).
   7  *
   8  * As far as I am concerned, the code I have written for this software
   9  * can be used freely for any purpose.  Any derived versions of this
  10  * software must be clearly marked as such, and if the derived work is
  11  * incompatible with the protocol description in the RFC file, it must be
  12  * called by a name other than "ssh" or "Secure Shell".
  13  *
  14  *
  15  * Copyright (c) 1999 Theo de Raadt.  All rights reserved.
  16  *
  17  * Redistribution and use in source and binary forms, with or without
  18  * modification, are permitted provided that the following conditions
  19  * are met:
  20  * 1. Redistributions of source code must retain the above copyright
  21  *    notice, this list of conditions and the following disclaimer.
  22  * 2. Redistributions in binary form must reproduce the above copyright
  23  *    notice, this list of conditions and the following disclaimer in the
  24  *    documentation and/or other materials provided with the distribution.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  27  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  28  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  29  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  30  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  31  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  35  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  *
  37  *
  38  * SSH2 support added by Markus Friedl.
  39  * Copyright (c) 1999, 2000, 2001 Markus Friedl.  All rights reserved.
  40  *
  41  * Redistribution and use in source and binary forms, with or without
  42  * modification, are permitted provided that the following conditions
  43  * are met:
  44  * 1. Redistributions of source code must retain the above copyright
  45  *    notice, this list of conditions and the following disclaimer.
  46  * 2. Redistributions in binary form must reproduce the above copyright
  47  *    notice, this list of conditions and the following disclaimer in the
  48  *    documentation and/or other materials provided with the distribution.
  49  *
  50  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  51  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  52  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  53  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  54  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  55  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  56  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  57  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  58  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  59  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  60  */
  61
  62 #include "includes.h"
  63
  64 #include <sys/types.h>
  65 #include <sys/ioctl.h>
  66 #ifdef HAVE_SYS_STAT_H
  67 # include <sys/stat.h>
  68 #endif
  69 #ifdef HAVE_SYS_TIME_H
  70 # include <sys/time.h>
  71 #endif
  72 #include <sys/socket.h>
  73
  74 #include <ctype.h>
  75 #include <errno.h>
  76 #ifdef HAVE_PATHS_H
  77 #include <paths.h>
  78 #endif
  79 #include <signal.h>
  80 #include <stdarg.h>
  81 #include <stdio.h>
  82 #include <stdlib.h>
  83 #include <string.h>
  84 #include <termios.h>
  85 #include <pwd.h>
  86 #include <unistd.h>
  87 #include <limits.h>
  88
  89 #include "openbsd-compat/sys-queue.h"
  90 #include "xmalloc.h"
  91 #include "ssh.h"
  92 #include "ssh2.h"
  93 #include "packet.h"
  94 #include "buffer.h"
  95 #include "compat.h"
  96 #include "channels.h"
  97 #include "dispatch.h"
  98 #include "key.h"
  99 #include "cipher.h"
 100 #include "kex.h"
 101 #include "myproposal.h"
 102 #include "log.h"
 103 #include "misc.h"
 104 #include "readconf.h"
 105 #include "clientloop.h"
 106 #include "sshconnect.h"
 107 #include "authfd.h"
 108 #include "atomicio.h"
 109 #include "sshpty.h"
 110 #include "match.h"
 111 #include "msg.h"
 112 #include "ssherr.h"
 113 #include "hostfile.h"
 114
 115 /* import options */
 116 extern Options options;
 117
 118 /* Flag indicating that stdin should be redirected from /dev/null. */
 119 extern int stdin_null_flag;
 120
 121 /* Flag indicating that no shell has been requested */
 122 extern int no_shell_flag;
 123
 124 /* Flag indicating that ssh should daemonise after authentication is complete */
 125 extern int fork_after_authentication_flag;
 126
 127 /* Control socket */
 128 extern int muxserver_sock; /* XXX use mux_client_cleanup() instead */
 129
 130 /*
 131  * Name of the host we are connecting to.  This is the name given on the
 132  * command line, or the HostName specified for the user-supplied name in a
 133  * configuration file.
 134  */
 135 extern char *host;
 136
 137 /*
 138  * Flag to indicate that we have received a window change signal which has
 139  * not yet been processed.  This will cause a message indicating the new
 140  * window size to be sent to the server a little later.  This is volatile
 141  * because this is updated in a signal handler.
 142  */
 143 static volatile sig_atomic_t received_window_change_signal = 0;
 144 static volatile sig_atomic_t received_signal = 0;
 145
 146 /* Flag indicating whether the user's terminal is in non-blocking mode. */
 147 static int in_non_blocking_mode = 0;
 148
 149 /* Time when backgrounded control master using ControlPersist should exit */
 150 static time_t control_persist_exit_time = 0;
 151
 152 /* Common data for the client loop code. */
 153 volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */
 154 static int last_was_cr;         /* Last character was a newline. */
 155 static int exit_status;         /* Used to store the command exit status. */
 156 static Buffer stderr_buffer;    /* Used for final exit message. */
 157 static int connection_in;       /* Connection to server (input). */
 158 static int connection_out;      /* Connection to server (output). */
 159 static int need_rekeying;       /* Set to non-zero if rekeying is requested. */
 160 static int session_closed;      /* In SSH2: login session closed. */
 161 static u_int x11_refuse_time;   /* If >0, refuse x11 opens after this time. */
 162
 163 static void client_init_dispatch(void);
 164 int     session_ident = -1;
 165
 166 /* Track escape per proto2 channel */
 167 struct escape_filter_ctx {
 168         int escape_pending;
 169         int escape_char;
 170 };
 171
 172 /* Context for channel confirmation replies */
 173 struct channel_reply_ctx {
 174         const char *request_type;
 175         int id;
 176         enum confirm_action action;
 177 };
 178
 179 /* Global request success/failure callbacks */
 180 /* XXX move to struct ssh? */
 181 struct global_confirm {
 182         TAILQ_ENTRY(global_confirm) entry;
 183         global_confirm_cb *cb;
 184         void *ctx;
 185         int ref_count;
 186 };
 187 TAILQ_HEAD(global_confirms, global_confirm);
 188 static struct global_confirms global_confirms =
 189     TAILQ_HEAD_INITIALIZER(global_confirms);
 190
 191 void ssh_process_session2_setup(int, int, int, Buffer *);
 192
 193 /* Restores stdin to blocking mode. */
 194
 195 static void
 196 leave_non_blocking(void)
 197 {
 198         if (in_non_blocking_mode) {
 199                 unset_nonblock(fileno(stdin));
 200                 in_non_blocking_mode = 0;
 201         }
 202 }
 203
 204 /*
 205  * Signal handler for the window change signal (SIGWINCH).  This just sets a
 206  * flag indicating that the window has changed.
 207  */
 208 /*ARGSUSED */
 209 static void
 210 window_change_handler(int sig)
 211 {
 212         received_window_change_signal = 1;
 213         signal(SIGWINCH, window_change_handler);
 214 }
 215
 216 /*
 217  * Signal handler for signals that cause the program to terminate.  These
 218  * signals must be trapped to restore terminal modes.
 219  */
 220 /*ARGSUSED */
 221 static void
 222 signal_handler(int sig)
 223 {
 224         received_signal = sig;
 225         quit_pending = 1;
 226 }
 227
 228 /*
 229  * Returns current time in seconds from Jan 1, 1970 with the maximum
 230  * available resolution.
 231  */
 232
 233 static double
 234 get_current_time(void)
 235 {
 236         struct timeval tv;
 237         gettimeofday(&tv, NULL);
 238         return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
 239 }
 240
 241 /*
 242  * Sets control_persist_exit_time to the absolute time when the
 243  * backgrounded control master should exit due to expiry of the
 244  * ControlPersist timeout.  Sets it to 0 if we are not a backgrounded
 245  * control master process, or if there is no ControlPersist timeout.
 246  */
 247 static void
 248 set_control_persist_exit_time(struct ssh *ssh)
 249 {
 250         if (muxserver_sock == -1 || !options.control_persist
 251             || options.control_persist_timeout == 0) {
 252                 /* not using a ControlPersist timeout */
 253                 control_persist_exit_time = 0;
 254         } else if (channel_still_open(ssh)) {
 255                 /* some client connections are still open */
 256                 if (control_persist_exit_time > 0)
 257                         debug2("%s: cancel scheduled exit", __func__);
 258                 control_persist_exit_time = 0;
 259         } else if (control_persist_exit_time <= 0) {
 260                 /* a client connection has recently closed */
 261                 control_persist_exit_time = monotime() +
 262                         (time_t)options.control_persist_timeout;
 263                 debug2("%s: schedule exit in %d seconds", __func__,
 264                     options.control_persist_timeout);
 265         }
 266         /* else we are already counting down to the timeout */
 267 }
 268
 269 #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_"
 270 static int
 271 client_x11_display_valid(const char *display)
 272 {
 273         size_t i, dlen;
 274
 275         if (display == NULL)
 276                 return 0;
 277
 278         dlen = strlen(display);
 279         for (i = 0; i < dlen; i++) {
 280                 if (!isalnum((u_char)display[i]) &&
 281                     strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) {
 282                         debug("Invalid character '%c' in DISPLAY", display[i]);
 283                         return 0;
 284                 }
 285         }
 286         return 1;
 287 }
 288
 289 #define SSH_X11_PROTO           "MIT-MAGIC-COOKIE-1"
 290 #define X11_TIMEOUT_SLACK       60
 291 int
 292 client_x11_get_proto(struct ssh *ssh, const char *display,
 293     const char *xauth_path, u_int trusted, u_int timeout,
 294     char **_proto, char **_data)
 295 {
 296         char cmd[1024], line[512], xdisplay[512];
 297         char xauthfile[PATH_MAX], xauthdir[PATH_MAX];
 298         static char proto[512], data[512];
 299         FILE *f;
 300         int got_data = 0, generated = 0, do_unlink = 0, r;
 301         struct stat st;
 302         u_int now, x11_timeout_real;
 303
 304         *_proto = proto;
 305         *_data = data;
 306         proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0';
 307
 308         if (!client_x11_display_valid(display)) {
 309                 if (display != NULL)
 310                         logit("DISPLAY \"%s\" invalid; disabling X11 forwarding",
 311                             display);
 312                 return -1;
 313         }
 314         if (xauth_path != NULL && stat(xauth_path, &st) == -1) {
 315                 debug("No xauth program.");
 316                 xauth_path = NULL;
 317         }
 318
 319         if (xauth_path != NULL) {
 320                 /*
 321                  * Handle FamilyLocal case where $DISPLAY does
 322                  * not match an authorization entry.  For this we
 323                  * just try "xauth list unix:displaynum.screennum".
 324                  * XXX: "localhost" match to determine FamilyLocal
 325                  *      is not perfect.
 326                  */
 327                 if (strncmp(display, "localhost:", 10) == 0) {
 328                         if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s",
 329                             display + 10)) < 0 ||
 330                             (size_t)r >= sizeof(xdisplay)) {
 331                                 error("%s: display name too long", __func__);
 332                                 return -1;
 333                         }
 334                         display = xdisplay;
 335                 }
 336                 if (trusted == 0) {
 337                         /*
 338                          * Generate an untrusted X11 auth cookie.
 339                          *
 340                          * The authentication cookie should briefly outlive
 341                          * ssh's willingness to forward X11 connections to
 342                          * avoid nasty fail-open behaviour in the X server.
 343                          */
 344                         mktemp_proto(xauthdir, sizeof(xauthdir));
 345                         if (mkdtemp(xauthdir) == NULL) {
 346                                 error("%s: mkdtemp: %s",
 347                                     __func__, strerror(errno));
 348                                 return -1;
 349                         }
 350                         do_unlink = 1;
 351                         if ((r = snprintf(xauthfile, sizeof(xauthfile),
 352                             "%s/xauthfile", xauthdir)) < 0 ||
 353                             (size_t)r >= sizeof(xauthfile)) {
 354                                 error("%s: xauthfile path too long", __func__);
 355                                 unlink(xauthfile);
 356                                 rmdir(xauthdir);
 357                                 return -1;
 358                         }
 359
 360                         if (timeout >= UINT_MAX - X11_TIMEOUT_SLACK)
 361                                 x11_timeout_real = UINT_MAX;
 362                         else
 363                                 x11_timeout_real = timeout + X11_TIMEOUT_SLACK;
 364                         if ((r = snprintf(cmd, sizeof(cmd),
 365                             "%s -f %s generate %s " SSH_X11_PROTO
 366                             " untrusted timeout %u 2>" _PATH_DEVNULL,
 367                             xauth_path, xauthfile, display,
 368                             x11_timeout_real)) < 0 ||
 369                             (size_t)r >= sizeof(cmd))
 370                                 fatal("%s: cmd too long", __func__);
 371                         debug2("%s: %s", __func__, cmd);
 372                         if (x11_refuse_time == 0) {
 373                                 now = monotime() + 1;
 374                                 if (UINT_MAX - timeout < now)
 375                                         x11_refuse_time = UINT_MAX;
 376                                 else
 377                                         x11_refuse_time = now + timeout;
 378                                 channel_set_x11_refuse_time(ssh,
 379                                     x11_refuse_time);
 380                         }
 381                         if (system(cmd) == 0)
 382                                 generated = 1;
 383                 }
 384
 385                 /*
 386                  * When in untrusted mode, we read the cookie only if it was
 387                  * successfully generated as an untrusted one in the step
 388                  * above.
 389                  */
 390                 if (trusted || generated) {
 391                         snprintf(cmd, sizeof(cmd),
 392                             "%s %s%s list %s 2>" _PATH_DEVNULL,
 393                             xauth_path,
 394                             generated ? "-f " : "" ,
 395                             generated ? xauthfile : "",
 396                             display);
 397                         debug2("x11_get_proto: %s", cmd);
 398                         f = popen(cmd, "r");
 399                         if (f && fgets(line, sizeof(line), f) &&
 400                             sscanf(line, "%*s %511s %511s", proto, data) == 2)
 401                                 got_data = 1;
 402                         if (f)
 403                                 pclose(f);
 404                 }
 405         }
 406
 407         if (do_unlink) {
 408                 unlink(xauthfile);
 409                 rmdir(xauthdir);
 410         }
 411
 412         /* Don't fall back to fake X11 data for untrusted forwarding */
 413         if (!trusted && !got_data) {
 414                 error("Warning: untrusted X11 forwarding setup failed: "
 415                     "xauth key data not generated");
 416                 return -1;
 417         }
 418
 419         /*
 420          * If we didn't get authentication data, just make up some
 421          * data.  The forwarding code will check the validity of the
 422          * response anyway, and substitute this data.  The X11
 423          * server, however, will ignore this fake data and use
 424          * whatever authentication mechanisms it was using otherwise
 425          * for the local connection.
 426          */
 427         if (!got_data) {
 428                 u_int8_t rnd[16];
 429                 u_int i;
 430
 431                 logit("Warning: No xauth data; "
 432                     "using fake authentication data for X11 forwarding.");
 433                 strlcpy(proto, SSH_X11_PROTO, sizeof proto);
 434                 arc4random_buf(rnd, sizeof(rnd));
 435                 for (i = 0; i < sizeof(rnd); i++) {
 436                         snprintf(data + 2 * i, sizeof data - 2 * i, "%02x",
 437                             rnd[i]);
 438                 }
 439         }
 440
 441         return 0;
 442 }
 443
 444 /*
 445  * Checks if the client window has changed, and sends a packet about it to
 446  * the server if so.  The actual change is detected elsewhere (by a software
 447  * interrupt on Unix); this just checks the flag and sends a message if
 448  * appropriate.
 449  */
 450
 451 static void
 452 client_check_window_change(struct ssh *ssh)
 453 {
 454         if (!received_window_change_signal)
 455                 return;
 456         /** XXX race */
 457         received_window_change_signal = 0;
 458
 459         debug2("%s: changed", __func__);
 460
 461         channel_send_window_changes(ssh);
 462 }
 463
 464 static int
 465 client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh)
 466 {
 467         struct global_confirm *gc;
 468
 469         if ((gc = TAILQ_FIRST(&global_confirms)) == NULL)
 470                 return 0;
 471         if (gc->cb != NULL)
 472                 gc->cb(ssh, type, seq, gc->ctx);
 473         if (--gc->ref_count <= 0) {
 474                 TAILQ_REMOVE(&global_confirms, gc, entry);
 475                 explicit_bzero(gc, sizeof(*gc));
 476                 free(gc);
 477         }
 478
 479         packet_set_alive_timeouts(0);
 480         return 0;
 481 }
 482
 483 static void
 484 server_alive_check(void)
 485 {
 486         if (packet_inc_alive_timeouts() > options.server_alive_count_max) {
 487                 logit("Timeout, server %s not responding.", host);
 488                 cleanup_exit(255);
 489         }
 490         packet_start(SSH2_MSG_GLOBAL_REQUEST);
 491         packet_put_cstring("keepalive@openssh.com");
 492         packet_put_char(1);     /* boolean: want reply */
 493         packet_send();
 494         /* Insert an empty placeholder to maintain ordering */
 495         client_register_global_confirm(NULL, NULL);
 496 }
 497
 498 /*
 499  * Waits until the client can do something (some data becomes available on
 500  * one of the file descriptors).
 501  */
 502 static void
 503 client_wait_until_can_do_something(struct ssh *ssh,
 504     fd_set **readsetp, fd_set **writesetp,
 505     int *maxfdp, u_int *nallocp, int rekeying)
 506 {
 507         struct timeval tv, *tvp;
 508         int timeout_secs;
 509         time_t minwait_secs = 0, server_alive_time = 0, now = monotime();
 510         int ret;
 511
 512         /* Add any selections by the channel mechanism. */
 513         channel_prepare_select(active_state, readsetp, writesetp, maxfdp,
 514             nallocp, &minwait_secs);
 515
 516         /* channel_prepare_select could have closed the last channel */
 517         if (session_closed && !channel_still_open(ssh) &&
 518             !packet_have_data_to_write()) {
 519                 /* clear mask since we did not call select() */
 520                 memset(*readsetp, 0, *nallocp);
 521                 memset(*writesetp, 0, *nallocp);
 522                 return;
 523         }
 524
 525         FD_SET(connection_in, *readsetp);
 526
 527         /* Select server connection if have data to write to the server. */
 528         if (packet_have_data_to_write())
 529                 FD_SET(connection_out, *writesetp);
 530
 531         /*
 532          * Wait for something to happen.  This will suspend the process until
 533          * some selected descriptor can be read, written, or has some other
 534          * event pending, or a timeout expires.
 535          */
 536
 537         timeout_secs = INT_MAX; /* we use INT_MAX to mean no timeout */
 538         if (options.server_alive_interval > 0) {
 539                 timeout_secs = options.server_alive_interval;
 540                 server_alive_time = now + options.server_alive_interval;
 541         }
 542         if (options.rekey_interval > 0 && !rekeying)
 543                 timeout_secs = MINIMUM(timeout_secs, packet_get_rekey_timeout());
 544         set_control_persist_exit_time(ssh);
 545         if (control_persist_exit_time > 0) {
 546                 timeout_secs = MINIMUM(timeout_secs,
 547                         control_persist_exit_time - now);
 548                 if (timeout_secs < 0)
 549                         timeout_secs = 0;
 550         }
 551         if (minwait_secs != 0)
 552                 timeout_secs = MINIMUM(timeout_secs, (int)minwait_secs);
 553         if (timeout_secs == INT_MAX)
 554                 tvp = NULL;
 555         else {
 556                 tv.tv_sec = timeout_secs;
 557                 tv.tv_usec = 0;
 558                 tvp = &tv;
 559         }
 560
 561         ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
 562         if (ret < 0) {
 563                 char buf[100];
 564
 565                 /*
 566                  * We have to clear the select masks, because we return.
 567                  * We have to return, because the mainloop checks for the flags
 568                  * set by the signal handlers.
 569                  */
 570                 memset(*readsetp, 0, *nallocp);
 571                 memset(*writesetp, 0, *nallocp);
 572
 573                 if (errno == EINTR)
 574                         return;
 575                 /* Note: we might still have data in the buffers. */
 576                 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno));
 577                 buffer_append(&stderr_buffer, buf, strlen(buf));
 578                 quit_pending = 1;
 579         } else if (ret == 0) {
 580                 /*
 581                  * Timeout.  Could have been either keepalive or rekeying.
 582                  * Keepalive we check here, rekeying is checked in clientloop.
 583                  */
 584                 if (server_alive_time != 0 && server_alive_time <= monotime())
 585                         server_alive_check();
 586         }
 587
 588 }
 589
 590 static void
 591 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr)
 592 {
 593         /* Flush stdout and stderr buffers. */
 594         if (buffer_len(bout) > 0)
 595                 atomicio(vwrite, fileno(stdout), buffer_ptr(bout),
 596                     buffer_len(bout));
 597         if (buffer_len(berr) > 0)
 598                 atomicio(vwrite, fileno(stderr), buffer_ptr(berr),
 599                     buffer_len(berr));
 600
 601         leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
 602
 603         sshbuf_reset(bin);
 604         sshbuf_reset(bout);
 605         sshbuf_reset(berr);
 606
 607         /* Send the suspend signal to the program itself. */
 608         kill(getpid(), SIGTSTP);
 609
 610         /* Reset window sizes in case they have changed */
 611         received_window_change_signal = 1;
 612
 613         enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
 614 }
 615
 616 static void
 617 client_process_net_input(fd_set *readset)
 618 {
 619         int len;
 620         char buf[SSH_IOBUFSZ];
 621
 622         /*
 623          * Read input from the server, and add any such data to the buffer of
 624          * the packet subsystem.
 625          */
 626         if (FD_ISSET(connection_in, readset)) {
 627                 /* Read as much as possible. */
 628                 len = read(connection_in, buf, sizeof(buf));
 629                 if (len == 0) {
 630                         /*
 631                          * Received EOF.  The remote host has closed the
 632                          * connection.
 633                          */
 634                         snprintf(buf, sizeof buf,
 635                             "Connection to %.300s closed by remote host.\r\n",
 636                             host);
 637                         buffer_append(&stderr_buffer, buf, strlen(buf));
 638                         quit_pending = 1;
 639                         return;
 640                 }
 641                 /*
 642                  * There is a kernel bug on Solaris that causes select to
 643                  * sometimes wake up even though there is no data available.
 644                  */
 645                 if (len < 0 &&
 646                     (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
 647                         len = 0;
 648
 649                 if (len < 0) {
 650                         /*
 651                          * An error has encountered.  Perhaps there is a
 652                          * network problem.
 653                          */
 654                         snprintf(buf, sizeof buf,
 655                             "Read from remote host %.300s: %.100s\r\n",
 656                             host, strerror(errno));
 657                         buffer_append(&stderr_buffer, buf, strlen(buf));
 658                         quit_pending = 1;
 659                         return;
 660                 }
 661                 packet_process_incoming(buf, len);
 662         }
 663 }
 664
 665 static void
 666 client_status_confirm(struct ssh *ssh, int type, Channel *c, void *ctx)
 667 {
 668         struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx;
 669         char errmsg[256];
 670         int tochan;
 671
 672         /*
 673          * If a TTY was explicitly requested, then a failure to allocate
 674          * one is fatal.
 675          */
 676         if (cr->action == CONFIRM_TTY &&
 677             (options.request_tty == REQUEST_TTY_FORCE ||
 678             options.request_tty == REQUEST_TTY_YES))
 679                 cr->action = CONFIRM_CLOSE;
 680
 681         /* XXX supress on mux _client_ quietmode */
 682         tochan = options.log_level >= SYSLOG_LEVEL_ERROR &&
 683             c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE;
 684
 685         if (type == SSH2_MSG_CHANNEL_SUCCESS) {
 686                 debug2("%s request accepted on channel %d",
 687                     cr->request_type, c->self);
 688         } else if (type == SSH2_MSG_CHANNEL_FAILURE) {
 689                 if (tochan) {
 690                         snprintf(errmsg, sizeof(errmsg),
 691                             "%s request failed\r\n", cr->request_type);
 692                 } else {
 693                         snprintf(errmsg, sizeof(errmsg),
 694                             "%s request failed on channel %d",
 695                             cr->request_type, c->self);
 696                 }
 697                 /* If error occurred on primary session channel, then exit */
 698                 if (cr->action == CONFIRM_CLOSE && c->self == session_ident)
 699                         fatal("%s", errmsg);
 700                 /*
 701                  * If error occurred on mux client, append to
 702                  * their stderr.
 703                  */
 704                 if (tochan) {
 705                         buffer_append(c->extended, errmsg, strlen(errmsg));
 706                 } else
 707                         error("%s", errmsg);
 708                 if (cr->action == CONFIRM_TTY) {
 709                         /*
 710                          * If a TTY allocation error occurred, then arrange
 711                          * for the correct TTY to leave raw mode.
 712                          */
 713                         if (c->self == session_ident)
 714                                 leave_raw_mode(0);
 715                         else
 716                                 mux_tty_alloc_failed(ssh, c);
 717                 } else if (cr->action == CONFIRM_CLOSE) {
 718                         chan_read_failed(ssh, c);
 719                         chan_write_failed(ssh, c);
 720                 }
 721         }
 722         free(cr);
 723 }
 724
 725 static void
 726 client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx)
 727 {
 728         free(ctx);
 729 }
 730
 731 void
 732 client_expect_confirm(struct ssh *ssh, int id, const char *request,
 733     enum confirm_action action)
 734 {
 735         struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr));
 736
 737         cr->request_type = request;
 738         cr->action = action;
 739
 740         channel_register_status_confirm(ssh, id, client_status_confirm,
 741             client_abandon_status_confirm, cr);
 742 }
 743
 744 void
 745 client_register_global_confirm(global_confirm_cb *cb, void *ctx)
 746 {
 747         struct global_confirm *gc, *last_gc;
 748
 749         /* Coalesce identical callbacks */
 750         last_gc = TAILQ_LAST(&global_confirms, global_confirms);
 751         if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) {
 752                 if (++last_gc->ref_count >= INT_MAX)
 753                         fatal("%s: last_gc->ref_count = %d",
 754                             __func__, last_gc->ref_count);
 755                 return;
 756         }
 757
 758         gc = xcalloc(1, sizeof(*gc));
 759         gc->cb = cb;
 760         gc->ctx = ctx;
 761         gc->ref_count = 1;
 762         TAILQ_INSERT_TAIL(&global_confirms, gc, entry);
 763 }
 764
 765 static void
 766 process_cmdline(struct ssh *ssh)
 767 {
 768         void (*handler)(int);
 769         char *s, *cmd;
 770         int ok, delete = 0, local = 0, remote = 0, dynamic = 0;
 771         struct Forward fwd;
 772
 773         memset(&fwd, 0, sizeof(fwd));
 774
 775         leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
 776         handler = signal(SIGINT, SIG_IGN);
 777         cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
 778         if (s == NULL)
 779                 goto out;
 780         while (isspace((u_char)*s))
 781                 s++;
 782         if (*s == '-')
 783                 s++;    /* Skip cmdline '-', if any */
 784         if (*s == '\0')
 785                 goto out;
 786
 787         if (*s == 'h' || *s == 'H' || *s == '?') {
 788                 logit("Commands:");
 789                 logit("      -L[bind_address:]port:host:hostport    "
 790                     "Request local forward");
 791                 logit("      -R[bind_address:]port:host:hostport    "
 792                     "Request remote forward");
 793                 logit("      -D[bind_address:]port                  "
 794                     "Request dynamic forward");
 795                 logit("      -KL[bind_address:]port                 "
 796                     "Cancel local forward");
 797                 logit("      -KR[bind_address:]port                 "
 798                     "Cancel remote forward");
 799                 logit("      -KD[bind_address:]port                 "
 800                     "Cancel dynamic forward");
 801                 if (!options.permit_local_command)
 802                         goto out;
 803                 logit("      !args                                  "
 804                     "Execute local command");
 805                 goto out;
 806         }
 807
 808         if (*s == '!' && options.permit_local_command) {
 809                 s++;
 810                 ssh_local_cmd(s);
 811                 goto out;
 812         }
 813
 814         if (*s == 'K') {
 815                 delete = 1;
 816                 s++;
 817         }
 818         if (*s == 'L')
 819                 local = 1;
 820         else if (*s == 'R')
 821                 remote = 1;
 822         else if (*s == 'D')
 823                 dynamic = 1;
 824         else {
 825                 logit("Invalid command.");
 826                 goto out;
 827         }
 828
 829         while (isspace((u_char)*++s))
 830                 ;
 831
 832         /* XXX update list of forwards in options */
 833         if (delete) {
 834                 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */
 835                 if (!parse_forward(&fwd, s, 1, 0)) {
 836                         logit("Bad forwarding close specification.");
 837                         goto out;
 838                 }
 839                 if (remote)
 840                         ok = channel_request_rforward_cancel(ssh, &fwd) == 0;
 841                 else if (dynamic)
 842                         ok = channel_cancel_lport_listener(ssh, &fwd,
 843                             0, &options.fwd_opts) > 0;
 844                 else
 845                         ok = channel_cancel_lport_listener(ssh, &fwd,
 846                             CHANNEL_CANCEL_PORT_STATIC,
 847                             &options.fwd_opts) > 0;
 848                 if (!ok) {
 849                         logit("Unknown port forwarding.");
 850                         goto out;
 851                 }
 852                 logit("Canceled forwarding.");
 853         } else {
 854                 if (!parse_forward(&fwd, s, dynamic, remote)) {
 855                         logit("Bad forwarding specification.");
 856                         goto out;
 857                 }
 858                 if (local || dynamic) {
 859                         if (!channel_setup_local_fwd_listener(ssh, &fwd,
 860                             &options.fwd_opts)) {
 861                                 logit("Port forwarding failed.");
 862                                 goto out;
 863                         }
 864                 } else {
 865                         if (channel_request_remote_forwarding(ssh, &fwd) < 0) {
 866                                 logit("Port forwarding failed.");
 867                                 goto out;
 868                         }
 869                 }
 870                 logit("Forwarding port.");
 871         }
 872
 873 out:
 874         signal(SIGINT, handler);
 875         enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
 876         free(cmd);
 877         free(fwd.listen_host);
 878         free(fwd.listen_path);
 879         free(fwd.connect_host);
 880         free(fwd.connect_path);
 881 }
 882
 883 /* reasons to suppress output of an escape command in help output */
 884 #define SUPPRESS_NEVER          0       /* never suppress, always show */
 885 #define SUPPRESS_MUXCLIENT      1       /* don't show in mux client sessions */
 886 #define SUPPRESS_MUXMASTER      2       /* don't show in mux master sessions */
 887 #define SUPPRESS_SYSLOG         4       /* don't show when logging to syslog */
 888 struct escape_help_text {
 889         const char *cmd;
 890         const char *text;
 891         unsigned int flags;
 892 };
 893 static struct escape_help_text esc_txt[] = {
 894     {".",  "terminate session", SUPPRESS_MUXMASTER},
 895     {".",  "terminate connection (and any multiplexed sessions)",
 896         SUPPRESS_MUXCLIENT},
 897     {"B",  "send a BREAK to the remote system", SUPPRESS_NEVER},
 898     {"C",  "open a command line", SUPPRESS_MUXCLIENT},
 899     {"R",  "request rekey", SUPPRESS_NEVER},
 900     {"V/v",  "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT},
 901     {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT},
 902     {"#",  "list forwarded connections", SUPPRESS_NEVER},
 903     {"&",  "background ssh (when waiting for connections to terminate)",
 904         SUPPRESS_MUXCLIENT},
 905     {"?", "this message", SUPPRESS_NEVER},
 906 };
 907
 908 static void
 909 print_escape_help(Buffer *b, int escape_char, int mux_client, int using_stderr)
 910 {
 911         unsigned int i, suppress_flags;
 912         char string[1024];
 913
 914         snprintf(string, sizeof string, "%c?\r\n"
 915             "Supported escape sequences:\r\n", escape_char);
 916         buffer_append(b, string, strlen(string));
 917
 918         suppress_flags =
 919             (mux_client ? SUPPRESS_MUXCLIENT : 0) |
 920             (mux_client ? 0 : SUPPRESS_MUXMASTER) |
 921             (using_stderr ? 0 : SUPPRESS_SYSLOG);
 922
 923         for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) {
 924                 if (esc_txt[i].flags & suppress_flags)
 925                         continue;
 926                 snprintf(string, sizeof string, " %c%-3s - %s\r\n",
 927                     escape_char, esc_txt[i].cmd, esc_txt[i].text);
 928                 buffer_append(b, string, strlen(string));
 929         }
 930
 931         snprintf(string, sizeof string,
 932             " %c%c   - send the escape character by typing it twice\r\n"
 933             "(Note that escapes are only recognized immediately after "
 934             "newline.)\r\n", escape_char, escape_char);
 935         buffer_append(b, string, strlen(string));
 936 }
 937
 938 /*
 939  * Process the characters one by one.
 940  */
 941 static int
 942 process_escapes(struct ssh *ssh, Channel *c,
 943     Buffer *bin, Buffer *bout, Buffer *berr,
 944     char *buf, int len)
 945 {
 946         char string[1024];
 947         pid_t pid;
 948         int bytes = 0;
 949         u_int i;
 950         u_char ch;
 951         char *s;
 952         struct escape_filter_ctx *efc = c->filter_ctx == NULL ?
 953             NULL : (struct escape_filter_ctx *)c->filter_ctx;
 954
 955         if (c->filter_ctx == NULL)
 956                 return 0;
 957
 958         if (len <= 0)
 959                 return (0);
 960
 961         for (i = 0; i < (u_int)len; i++) {
 962                 /* Get one character at a time. */
 963                 ch = buf[i];
 964
 965                 if (efc->escape_pending) {
 966                         /* We have previously seen an escape character. */
 967                         /* Clear the flag now. */
 968                         efc->escape_pending = 0;
 969
 970                         /* Process the escaped character. */
 971                         switch (ch) {
 972                         case '.':
 973                                 /* Terminate the connection. */
 974                                 snprintf(string, sizeof string, "%c.\r\n",
 975                                     efc->escape_char);
 976                                 buffer_append(berr, string, strlen(string));
 977
 978                                 if (c && c->ctl_chan != -1) {
 979                                         chan_read_failed(ssh, c);
 980                                         chan_write_failed(ssh, c);
 981                                         if (c->detach_user) {
 982                                                 c->detach_user(ssh,
 983                                                     c->self, NULL);
 984                                         }
 985                                         c->type = SSH_CHANNEL_ABANDONED;
 986                                         buffer_clear(c->input);
 987                                         chan_ibuf_empty(ssh, c);
 988                                         return 0;
 989                                 } else
 990                                         quit_pending = 1;
 991                                 return -1;
 992
 993                         case 'Z' - 64:
 994                                 /* XXX support this for mux clients */
 995                                 if (c && c->ctl_chan != -1) {
 996                                         char b[16];
 997  noescape:
 998                                         if (ch == 'Z' - 64)
 999                                                 snprintf(b, sizeof b, "^Z");
1000                                         else
1001                                                 snprintf(b, sizeof b, "%c", ch);
1002                                         snprintf(string, sizeof string,
1003                                             "%c%s escape not available to "
1004                                             "multiplexed sessions\r\n",
1005                                             efc->escape_char, b);
1006                                         buffer_append(berr, string,
1007                                             strlen(string));
1008                                         continue;
1009                                 }
1010                                 /* Suspend the program. Inform the user */
1011                                 snprintf(string, sizeof string,
1012                                     "%c^Z [suspend ssh]\r\n", efc->escape_char);
1013                                 buffer_append(berr, string, strlen(string));
1014
1015                                 /* Restore terminal modes and suspend. */
1016                                 client_suspend_self(bin, bout, berr);
1017
1018                                 /* We have been continued. */
1019                                 continue;
1020
1021                         case 'B':
1022                                 snprintf(string, sizeof string,
1023                                     "%cB\r\n", efc->escape_char);
1024                                 buffer_append(berr, string, strlen(string));
1025                                 channel_request_start(ssh, c->self, "break", 0);
1026                                 packet_put_int(1000);
1027                                 packet_send();
1028                                 continue;
1029
1030                         case 'R':
1031                                 if (datafellows & SSH_BUG_NOREKEY)
1032                                         logit("Server does not "
1033                                             "support re-keying");
1034                                 else
1035                                         need_rekeying = 1;
1036                                 continue;
1037
1038                         case 'V':
1039                                 /* FALLTHROUGH */
1040                         case 'v':
1041                                 if (c && c->ctl_chan != -1)
1042                                         goto noescape;
1043                                 if (!log_is_on_stderr()) {
1044                                         snprintf(string, sizeof string,
1045                                             "%c%c [Logging to syslog]\r\n",
1046                                              efc->escape_char, ch);
1047                                         buffer_append(berr, string,
1048                                             strlen(string));
1049                                         continue;
1050                                 }
1051                                 if (ch == 'V' && options.log_level >
1052                                     SYSLOG_LEVEL_QUIET)
1053                                         log_change_level(--options.log_level);
1054                                 if (ch == 'v' && options.log_level <
1055                                     SYSLOG_LEVEL_DEBUG3)
1056                                         log_change_level(++options.log_level);
1057                                 snprintf(string, sizeof string,
1058                                     "%c%c [LogLevel %s]\r\n",
1059                                     efc->escape_char, ch,
1060                                     log_level_name(options.log_level));
1061                                 buffer_append(berr, string, strlen(string));
1062                                 continue;
1063
1064                         case '&':
1065                                 if (c && c->ctl_chan != -1)
1066                                         goto noescape;
1067                                 /*
1068                                  * Detach the program (continue to serve
1069                                  * connections, but put in background and no
1070                                  * more new connections).
1071                                  */
1072                                 /* Restore tty modes. */
1073                                 leave_raw_mode(
1074                                     options.request_tty == REQUEST_TTY_FORCE);
1075
1076                                 /* Stop listening for new connections. */
1077                                 channel_stop_listening(ssh);
1078
1079                                 snprintf(string, sizeof string,
1080                                     "%c& [backgrounded]\n", efc->escape_char);
1081                                 buffer_append(berr, string, strlen(string));
1082
1083                                 /* Fork into background. */
1084                                 pid = fork();
1085                                 if (pid < 0) {
1086                                         error("fork: %.100s", strerror(errno));
1087                                         continue;
1088                                 }
1089                                 if (pid != 0) { /* This is the parent. */
1090                                         /* The parent just exits. */
1091                                         exit(0);
1092                                 }
1093                                 /* The child continues serving connections. */
1094                                 buffer_append(bin, "\004", 1);
1095                                 /* fake EOF on stdin */
1096                                 return -1;
1097                         case '?':
1098                                 print_escape_help(berr, efc->escape_char,
1099                                     (c && c->ctl_chan != -1),
1100                                     log_is_on_stderr());
1101                                 continue;
1102
1103                         case '#':
1104                                 snprintf(string, sizeof string, "%c#\r\n",
1105                                     efc->escape_char);
1106                                 buffer_append(berr, string, strlen(string));
1107                                 s = channel_open_message(ssh);
1108                                 buffer_append(berr, s, strlen(s));
1109                                 free(s);
1110                                 continue;
1111
1112                         case 'C':
1113                                 if (c && c->ctl_chan != -1)
1114                                         goto noescape;
1115                                 process_cmdline(ssh);
1116                                 continue;
1117
1118                         default:
1119                                 if (ch != efc->escape_char) {
1120                                         buffer_put_char(bin, efc->escape_char);
1121                                         bytes++;
1122                                 }
1123                                 /* Escaped characters fall through here */
1124                                 break;
1125                         }
1126                 } else {
1127                         /*
1128                          * The previous character was not an escape char.
1129                          * Check if this is an escape.
1130                          */
1131                         if (last_was_cr && ch == efc->escape_char) {
1132                                 /*
1133                                  * It is. Set the flag and continue to
1134                                  * next character.
1135                                  */
1136                                 efc->escape_pending = 1;
1137                                 continue;
1138                         }
1139                 }
1140
1141                 /*
1142                  * Normal character.  Record whether it was a newline,
1143                  * and append it to the buffer.
1144                  */
1145                 last_was_cr = (ch == '\r' || ch == '\n');
1146                 buffer_put_char(bin, ch);
1147                 bytes++;
1148         }
1149         return bytes;
1150 }
1151
1152 /*
1153  * Get packets from the connection input buffer, and process them as long as
1154  * there are packets available.
1155  *
1156  * Any unknown packets received during the actual
1157  * session cause the session to terminate.  This is
1158  * intended to make debugging easier since no
1159  * confirmations are sent.  Any compatible protocol
1160  * extensions must be negotiated during the
1161  * preparatory phase.
1162  */
1163
1164 static void
1165 client_process_buffered_input_packets(void)
1166 {
1167         ssh_dispatch_run_fatal(active_state, DISPATCH_NONBLOCK, &quit_pending);
1168 }
1169
1170 /* scan buf[] for '~' before sending data to the peer */
1171
1172 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */
1173 void *
1174 client_new_escape_filter_ctx(int escape_char)
1175 {
1176         struct escape_filter_ctx *ret;
1177
1178         ret = xcalloc(1, sizeof(*ret));
1179         ret->escape_pending = 0;
1180         ret->escape_char = escape_char;
1181         return (void *)ret;
1182 }
1183
1184 /* Free the escape filter context on channel free */
1185 void
1186 client_filter_cleanup(struct ssh *ssh, int cid, void *ctx)
1187 {
1188         free(ctx);
1189 }
1190
1191 int
1192 client_simple_escape_filter(struct ssh *ssh, Channel *c, char *buf, int len)
1193 {
1194         if (c->extended_usage != CHAN_EXTENDED_WRITE)
1195                 return 0;
1196
1197         return process_escapes(ssh, c, c->input, c->output, c->extended,
1198             buf, len);
1199 }
1200
1201 static void
1202 client_channel_closed(struct ssh *ssh, int id, void *arg)
1203 {
1204         channel_cancel_cleanup(ssh, id);
1205         session_closed = 1;
1206         leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1207 }
1208
1209 /*
1210  * Implements the interactive session with the server.  This is called after
1211  * the user has been authenticated, and a command has been started on the
1212  * remote host.  If escape_char != SSH_ESCAPECHAR_NONE, it is the character
1213  * used as an escape character for terminating or suspending the session.
1214  */
1215 int
1216 client_loop(struct ssh *ssh, int have_pty, int escape_char_arg,
1217     int ssh2_chan_id)
1218 {
1219         fd_set *readset = NULL, *writeset = NULL;
1220         double start_time, total_time;
1221         int r, max_fd = 0, max_fd2 = 0, len;
1222         u_int64_t ibytes, obytes;
1223         u_int nalloc = 0;
1224         char buf[100];
1225
1226         debug("Entering interactive session.");
1227
1228         if (options.control_master &&
1229             !option_clear_or_none(options.control_path)) {
1230                 debug("pledge: id");
1231                 if (pledge("stdio rpath wpath cpath unix inet dns recvfd proc exec id tty",
1232                     NULL) == -1)
1233                         fatal("%s pledge(): %s", __func__, strerror(errno));
1234
1235         } else if (options.forward_x11 || options.permit_local_command) {
1236                 debug("pledge: exec");
1237                 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty",
1238                     NULL) == -1)
1239                         fatal("%s pledge(): %s", __func__, strerror(errno));
1240
1241         } else if (options.update_hostkeys) {
1242                 debug("pledge: filesystem full");
1243                 if (pledge("stdio rpath wpath cpath unix inet dns proc tty",
1244                     NULL) == -1)
1245                         fatal("%s pledge(): %s", __func__, strerror(errno));
1246
1247         } else if (!option_clear_or_none(options.proxy_command) ||
1248             fork_after_authentication_flag) {
1249                 debug("pledge: proc");
1250                 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1)
1251                         fatal("%s pledge(): %s", __func__, strerror(errno));
1252
1253         } else {
1254                 debug("pledge: network");
1255                 if (pledge("stdio unix inet dns proc tty", NULL) == -1)
1256                         fatal("%s pledge(): %s", __func__, strerror(errno));
1257         }
1258
1259         start_time = get_current_time();
1260
1261         /* Initialize variables. */
1262         last_was_cr = 1;
1263         exit_status = -1;
1264         connection_in = packet_get_connection_in();
1265         connection_out = packet_get_connection_out();
1266         max_fd = MAXIMUM(connection_in, connection_out);
1267
1268         quit_pending = 0;
1269
1270         /* Initialize buffers. */
1271         buffer_init(&stderr_buffer);
1272
1273         client_init_dispatch();
1274
1275         /*
1276          * Set signal handlers, (e.g. to restore non-blocking mode)
1277          * but don't overwrite SIG_IGN, matches behaviour from rsh(1)
1278          */
1279         if (signal(SIGHUP, SIG_IGN) != SIG_IGN)
1280                 signal(SIGHUP, signal_handler);
1281         if (signal(SIGINT, SIG_IGN) != SIG_IGN)
1282                 signal(SIGINT, signal_handler);
1283         if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
1284                 signal(SIGQUIT, signal_handler);
1285         if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
1286                 signal(SIGTERM, signal_handler);
1287         signal(SIGWINCH, window_change_handler);
1288
1289         if (have_pty)
1290                 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1291
1292         session_ident = ssh2_chan_id;
1293         if (session_ident != -1) {
1294                 if (escape_char_arg != SSH_ESCAPECHAR_NONE) {
1295                         channel_register_filter(ssh, session_ident,
1296                             client_simple_escape_filter, NULL,
1297                             client_filter_cleanup,
1298                             client_new_escape_filter_ctx(
1299                             escape_char_arg));
1300                 }
1301                 channel_register_cleanup(ssh, session_ident,
1302                     client_channel_closed, 0);
1303         }
1304
1305         /* Main loop of the client for the interactive session mode. */
1306         while (!quit_pending) {
1307
1308                 /* Process buffered packets sent by the server. */
1309                 client_process_buffered_input_packets();
1310
1311                 if (session_closed && !channel_still_open(ssh))
1312                         break;
1313
1314                 if (ssh_packet_is_rekeying(ssh)) {
1315                         debug("rekeying in progress");
1316                 } else if (need_rekeying) {
1317                         /* manual rekey request */
1318                         debug("need rekeying");
1319                         if ((r = kex_start_rekex(ssh)) != 0)
1320                                 fatal("%s: kex_start_rekex: %s", __func__,
1321                                     ssh_err(r));
1322                         need_rekeying = 0;
1323                 } else {
1324                         /*
1325                          * Make packets from buffered channel data, and
1326                          * enqueue them for sending to the server.
1327                          */
1328                         if (packet_not_very_much_data_to_write())
1329                                 channel_output_poll(ssh);
1330
1331                         /*
1332                          * Check if the window size has changed, and buffer a
1333                          * message about it to the server if so.
1334                          */
1335                         client_check_window_change(ssh);
1336
1337                         if (quit_pending)
1338                                 break;
1339                 }
1340                 /*
1341                  * Wait until we have something to do (something becomes
1342                  * available on one of the descriptors).
1343                  */
1344                 max_fd2 = max_fd;
1345                 client_wait_until_can_do_something(ssh, &readset, &writeset,
1346                     &max_fd2, &nalloc, ssh_packet_is_rekeying(ssh));
1347
1348                 if (quit_pending)
1349                         break;
1350
1351                 /* Do channel operations unless rekeying in progress. */
1352                 if (!ssh_packet_is_rekeying(ssh))
1353                         channel_after_select(ssh, readset, writeset);
1354
1355                 /* Buffer input from the connection.  */
1356                 client_process_net_input(readset);
1357
1358                 if (quit_pending)
1359                         break;
1360
1361                 /*
1362                  * Send as much buffered packet data as possible to the
1363                  * sender.
1364                  */
1365                 if (FD_ISSET(connection_out, writeset))
1366                         packet_write_poll();
1367
1368                 /*
1369                  * If we are a backgrounded control master, and the
1370                  * timeout has expired without any active client
1371                  * connections, then quit.
1372                  */
1373                 if (control_persist_exit_time > 0) {
1374                         if (monotime() >= control_persist_exit_time) {
1375                                 debug("ControlPersist timeout expired");
1376                                 break;
1377                         }
1378                 }
1379         }
1380         free(readset);
1381         free(writeset);
1382
1383         /* Terminate the session. */
1384
1385         /* Stop watching for window change. */
1386         signal(SIGWINCH, SIG_DFL);
1387
1388         packet_start(SSH2_MSG_DISCONNECT);
1389         packet_put_int(SSH2_DISCONNECT_BY_APPLICATION);
1390         packet_put_cstring("disconnected by user");
1391         packet_put_cstring(""); /* language tag */
1392         packet_send();
1393         packet_write_wait();
1394
1395         channel_free_all(ssh);
1396
1397         if (have_pty)
1398                 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1399
1400         /* restore blocking io */
1401         if (!isatty(fileno(stdin)))
1402                 unset_nonblock(fileno(stdin));
1403         if (!isatty(fileno(stdout)))
1404                 unset_nonblock(fileno(stdout));
1405         if (!isatty(fileno(stderr)))
1406                 unset_nonblock(fileno(stderr));
1407
1408         /*
1409          * If there was no shell or command requested, there will be no remote
1410          * exit status to be returned.  In that case, clear error code if the
1411          * connection was deliberately terminated at this end.
1412          */
1413         if (no_shell_flag && received_signal == SIGTERM) {
1414                 received_signal = 0;
1415                 exit_status = 0;
1416         }
1417
1418         if (received_signal) {
1419                 verbose("Killed by signal %d.", (int) received_signal);
1420                 cleanup_exit(0);
1421         }
1422
1423         /*
1424          * In interactive mode (with pseudo tty) display a message indicating
1425          * that the connection has been closed.
1426          */
1427         if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
1428                 snprintf(buf, sizeof buf,
1429                     "Connection to %.64s closed.\r\n", host);
1430                 buffer_append(&stderr_buffer, buf, strlen(buf));
1431         }
1432
1433         /* Output any buffered data for stderr. */
1434         if (buffer_len(&stderr_buffer) > 0) {
1435                 len = atomicio(vwrite, fileno(stderr),
1436                     buffer_ptr(&stderr_buffer), buffer_len(&stderr_buffer));
1437                 if (len < 0 || (u_int)len != buffer_len(&stderr_buffer))
1438                         error("Write failed flushing stderr buffer.");
1439                 else
1440                         buffer_consume(&stderr_buffer, len);
1441         }
1442
1443         /* Clear and free any buffers. */
1444         explicit_bzero(buf, sizeof(buf));
1445         buffer_free(&stderr_buffer);
1446
1447         /* Report bytes transferred, and transfer rates. */
1448         total_time = get_current_time() - start_time;
1449         packet_get_bytes(&ibytes, &obytes);
1450         verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds",
1451             (unsigned long long)obytes, (unsigned long long)ibytes, total_time);
1452         if (total_time > 0)
1453                 verbose("Bytes per second: sent %.1f, received %.1f",
1454                     obytes / total_time, ibytes / total_time);
1455         /* Return the exit status of the program. */
1456         debug("Exit status %d", exit_status);
1457         return exit_status;
1458 }
1459
1460 /*********/
1461
1462 static Channel *
1463 client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type,
1464     int rchan, u_int rwindow, u_int rmaxpack)
1465 {
1466         Channel *c = NULL;
1467         struct sshbuf *b = NULL;
1468         char *listen_address, *originator_address;
1469         u_short listen_port, originator_port;
1470         int r;
1471
1472         /* Get rest of the packet */
1473         listen_address = packet_get_string(NULL);
1474         listen_port = packet_get_int();
1475         originator_address = packet_get_string(NULL);
1476         originator_port = packet_get_int();
1477         packet_check_eom();
1478
1479         debug("%s: listen %s port %d, originator %s port %d", __func__,
1480             listen_address, listen_port, originator_address, originator_port);
1481
1482         c = channel_connect_by_listen_address(ssh, listen_address, listen_port,
1483             "forwarded-tcpip", originator_address);
1484
1485         if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) {
1486                 if ((b = sshbuf_new()) == NULL) {
1487                         error("%s: alloc reply", __func__);
1488                         goto out;
1489                 }
1490                 /* reconstruct and send to muxclient */
1491                 if ((r = sshbuf_put_u8(b, 0)) != 0 ||   /* padlen */
1492                     (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 ||
1493                     (r = sshbuf_put_cstring(b, request_type)) != 0 ||
1494                     (r = sshbuf_put_u32(b, rchan)) != 0 ||
1495                     (r = sshbuf_put_u32(b, rwindow)) != 0 ||
1496                     (r = sshbuf_put_u32(b, rmaxpack)) != 0 ||
1497                     (r = sshbuf_put_cstring(b, listen_address)) != 0 ||
1498                     (r = sshbuf_put_u32(b, listen_port)) != 0 ||
1499                     (r = sshbuf_put_cstring(b, originator_address)) != 0 ||
1500                     (r = sshbuf_put_u32(b, originator_port)) != 0 ||
1501                     (r = sshbuf_put_stringb(c->output, b)) != 0) {
1502                         error("%s: compose for muxclient %s", __func__,
1503                             ssh_err(r));
1504                         goto out;
1505                 }
1506         }
1507
1508  out:
1509         sshbuf_free(b);
1510         free(originator_address);
1511         free(listen_address);
1512         return c;
1513 }
1514
1515 static Channel *
1516 client_request_forwarded_streamlocal(struct ssh *ssh,
1517     const char *request_type, int rchan)
1518 {
1519         Channel *c = NULL;
1520         char *listen_path;
1521
1522         /* Get the remote path. */
1523         listen_path = packet_get_string(NULL);
1524         /* XXX: Skip reserved field for now. */
1525         if (packet_get_string_ptr(NULL) == NULL)
1526                 fatal("%s: packet_get_string_ptr failed", __func__);
1527         packet_check_eom();
1528
1529         debug("%s: %s", __func__, listen_path);
1530
1531         c = channel_connect_by_listen_path(ssh, listen_path,
1532             "forwarded-streamlocal@openssh.com", "forwarded-streamlocal");
1533         free(listen_path);
1534         return c;
1535 }
1536
1537 static Channel *
1538 client_request_x11(struct ssh *ssh, const char *request_type, int rchan)
1539 {
1540         Channel *c = NULL;
1541         char *originator;
1542         u_short originator_port;
1543         int sock;
1544
1545         if (!options.forward_x11) {
1546                 error("Warning: ssh server tried X11 forwarding.");
1547                 error("Warning: this is probably a break-in attempt by a "
1548                     "malicious server.");
1549                 return NULL;
1550         }
1551         if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) {
1552                 verbose("Rejected X11 connection after ForwardX11Timeout "
1553                     "expired");
1554                 return NULL;
1555         }
1556         originator = packet_get_string(NULL);
1557         if (datafellows & SSH_BUG_X11FWD) {
1558                 debug2("buggy server: x11 request w/o originator_port");
1559                 originator_port = 0;
1560         } else {
1561                 originator_port = packet_get_int();
1562         }
1563         packet_check_eom();
1564         /* XXX check permission */
1565         debug("client_request_x11: request from %s %d", originator,
1566             originator_port);
1567         free(originator);
1568         sock = x11_connect_display(ssh);
1569         if (sock < 0)
1570                 return NULL;
1571         c = channel_new(ssh, "x11",
1572             SSH_CHANNEL_X11_OPEN, sock, sock, -1,
1573             CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1);
1574         c->force_drain = 1;
1575         return c;
1576 }
1577
1578 static Channel *
1579 client_request_agent(struct ssh *ssh, const char *request_type, int rchan)
1580 {
1581         Channel *c = NULL;
1582         int r, sock;
1583
1584         if (!options.forward_agent) {
1585                 error("Warning: ssh server tried agent forwarding.");
1586                 error("Warning: this is probably a break-in attempt by a "
1587                     "malicious server.");
1588                 return NULL;
1589         }
1590         if ((r = ssh_get_authentication_socket(&sock)) != 0) {
1591                 if (r != SSH_ERR_AGENT_NOT_PRESENT)
1592                         debug("%s: ssh_get_authentication_socket: %s",
1593                             __func__, ssh_err(r));
1594                 return NULL;
1595         }
1596         c = channel_new(ssh, "authentication agent connection",
1597             SSH_CHANNEL_OPEN, sock, sock, -1,
1598             CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0,
1599             "authentication agent connection", 1);
1600         c->force_drain = 1;
1601         return c;
1602 }
1603
1604 int
1605 client_request_tun_fwd(struct ssh *ssh, int tun_mode,
1606     int local_tun, int remote_tun)
1607 {
1608         Channel *c;
1609         int fd;
1610
1611         if (tun_mode == SSH_TUNMODE_NO)
1612                 return 0;
1613
1614         debug("Requesting tun unit %d in mode %d", local_tun, tun_mode);
1615
1616         /* Open local tunnel device */
1617         if ((fd = tun_open(local_tun, tun_mode)) == -1) {
1618                 error("Tunnel device open failed.");
1619                 return -1;
1620         }
1621
1622         c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1,
1623             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1624         c->datagram = 1;
1625
1626 #if defined(SSH_TUN_FILTER)
1627         if (options.tun_open == SSH_TUNMODE_POINTOPOINT)
1628                 channel_register_filter(ssh, c->self, sys_tun_infilter,
1629                     sys_tun_outfilter, NULL, NULL);
1630 #endif
1631
1632         packet_start(SSH2_MSG_CHANNEL_OPEN);
1633         packet_put_cstring("tun@openssh.com");
1634         packet_put_int(c->self);
1635         packet_put_int(c->local_window_max);
1636         packet_put_int(c->local_maxpacket);
1637         packet_put_int(tun_mode);
1638         packet_put_int(remote_tun);
1639         packet_send();
1640
1641         return 0;
1642 }
1643
1644 /* XXXX move to generic input handler */
1645 static int
1646 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh)
1647 {
1648         Channel *c = NULL;
1649         char *ctype;
1650         int rchan;
1651         u_int rmaxpack, rwindow, len;
1652
1653         ctype = packet_get_string(&len);
1654         rchan = packet_get_int();
1655         rwindow = packet_get_int();
1656         rmaxpack = packet_get_int();
1657
1658         debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
1659             ctype, rchan, rwindow, rmaxpack);
1660
1661         if (strcmp(ctype, "forwarded-tcpip") == 0) {
1662                 c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow,
1663                     rmaxpack);
1664         } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) {
1665                 c = client_request_forwarded_streamlocal(ssh, ctype, rchan);
1666         } else if (strcmp(ctype, "x11") == 0) {
1667                 c = client_request_x11(ssh, ctype, rchan);
1668         } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) {
1669                 c = client_request_agent(ssh, ctype, rchan);
1670         }
1671         if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) {
1672                 debug3("proxied to downstream: %s", ctype);
1673         } else if (c != NULL) {
1674                 debug("confirm %s", ctype);
1675                 c->remote_id = rchan;
1676                 c->have_remote_id = 1;
1677                 c->remote_window = rwindow;
1678                 c->remote_maxpacket = rmaxpack;
1679                 if (c->type != SSH_CHANNEL_CONNECTING) {
1680                         packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1681                         packet_put_int(c->remote_id);
1682                         packet_put_int(c->self);
1683                         packet_put_int(c->local_window);
1684                         packet_put_int(c->local_maxpacket);
1685                         packet_send();
1686                 }
1687         } else {
1688                 debug("failure %s", ctype);
1689                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1690                 packet_put_int(rchan);
1691                 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1692                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1693                         packet_put_cstring("open failed");
1694                         packet_put_cstring("");
1695                 }
1696                 packet_send();
1697         }
1698         free(ctype);
1699         return 0;
1700 }
1701
1702 static int
1703 client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh)
1704 {
1705         Channel *c = NULL;
1706         int exitval, id, reply, success = 0;
1707         char *rtype;
1708
1709         id = packet_get_int();
1710         c = channel_lookup(ssh, id);
1711         if (channel_proxy_upstream(c, type, seq, ssh))
1712                 return 0;
1713         rtype = packet_get_string(NULL);
1714         reply = packet_get_char();
1715
1716         debug("client_input_channel_req: channel %d rtype %s reply %d",
1717             id, rtype, reply);
1718
1719         if (id == -1) {
1720                 error("client_input_channel_req: request for channel -1");
1721         } else if (c == NULL) {
1722                 error("client_input_channel_req: channel %d: "
1723                     "unknown channel", id);
1724         } else if (strcmp(rtype, "eow@openssh.com") == 0) {
1725                 packet_check_eom();
1726                 chan_rcvd_eow(ssh, c);
1727         } else if (strcmp(rtype, "exit-status") == 0) {
1728                 exitval = packet_get_int();
1729                 if (c->ctl_chan != -1) {
1730                         mux_exit_message(ssh, c, exitval);
1731                         success = 1;
1732                 } else if (id == session_ident) {
1733                         /* Record exit value of local session */
1734                         success = 1;
1735                         exit_status = exitval;
1736                 } else {
1737                         /* Probably for a mux channel that has already closed */
1738                         debug("%s: no sink for exit-status on channel %d",
1739                             __func__, id);
1740                 }
1741                 packet_check_eom();
1742         }
1743         if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) {
1744                 if (!c->have_remote_id)
1745                         fatal("%s: channel %d: no remote_id",
1746                             __func__, c->self);
1747                 packet_start(success ?
1748                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1749                 packet_put_int(c->remote_id);
1750                 packet_send();
1751         }
1752         free(rtype);
1753         return 0;
1754 }
1755
1756 struct hostkeys_update_ctx {
1757         /* The hostname and (optionally) IP address string for the server */
1758         char *host_str, *ip_str;
1759
1760         /*
1761          * Keys received from the server and a flag for each indicating
1762          * whether they already exist in known_hosts.
1763          * keys_seen is filled in by hostkeys_find() and later (for new
1764          * keys) by client_global_hostkeys_private_confirm().
1765          */
1766         struct sshkey **keys;
1767         int *keys_seen;
1768         size_t nkeys, nnew;
1769
1770         /*
1771          * Keys that are in known_hosts, but were not present in the update
1772          * from the server (i.e. scheduled to be deleted).
1773          * Filled in by hostkeys_find().
1774          */
1775         struct sshkey **old_keys;
1776         size_t nold;
1777 };
1778
1779 static void
1780 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx)
1781 {
1782         size_t i;
1783
1784         if (ctx == NULL)
1785                 return;
1786         for (i = 0; i < ctx->nkeys; i++)
1787                 sshkey_free(ctx->keys[i]);
1788         free(ctx->keys);
1789         free(ctx->keys_seen);
1790         for (i = 0; i < ctx->nold; i++)
1791                 sshkey_free(ctx->old_keys[i]);
1792         free(ctx->old_keys);
1793         free(ctx->host_str);
1794         free(ctx->ip_str);
1795         free(ctx);
1796 }
1797
1798 static int
1799 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx)
1800 {
1801         struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx;
1802         size_t i;
1803         struct sshkey **tmp;
1804
1805         if (l->status != HKF_STATUS_MATCHED || l->key == NULL)
1806                 return 0;
1807
1808         /* Mark off keys we've already seen for this host */
1809         for (i = 0; i < ctx->nkeys; i++) {
1810                 if (sshkey_equal(l->key, ctx->keys[i])) {
1811                         debug3("%s: found %s key at %s:%ld", __func__,
1812                             sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum);
1813                         ctx->keys_seen[i] = 1;
1814                         return 0;
1815                 }
1816         }
1817         /* This line contained a key that not offered by the server */
1818         debug3("%s: deprecated %s key at %s:%ld", __func__,
1819             sshkey_ssh_name(l->key), l->path, l->linenum);
1820         if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1,
1821             sizeof(*ctx->old_keys))) == NULL)
1822                 fatal("%s: recallocarray failed nold = %zu",
1823                     __func__, ctx->nold);
1824         ctx->old_keys = tmp;
1825         ctx->old_keys[ctx->nold++] = l->key;
1826         l->key = NULL;
1827
1828         return 0;
1829 }
1830
1831 static void
1832 update_known_hosts(struct hostkeys_update_ctx *ctx)
1833 {
1834         int r, was_raw = 0;
1835         int loglevel = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK ?
1836             SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE;
1837         char *fp, *response;
1838         size_t i;
1839
1840         for (i = 0; i < ctx->nkeys; i++) {
1841                 if (ctx->keys_seen[i] != 2)
1842                         continue;
1843                 if ((fp = sshkey_fingerprint(ctx->keys[i],
1844                     options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
1845                         fatal("%s: sshkey_fingerprint failed", __func__);
1846                 do_log2(loglevel, "Learned new hostkey: %s %s",
1847                     sshkey_type(ctx->keys[i]), fp);
1848                 free(fp);
1849         }
1850         for (i = 0; i < ctx->nold; i++) {
1851                 if ((fp = sshkey_fingerprint(ctx->old_keys[i],
1852                     options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
1853                         fatal("%s: sshkey_fingerprint failed", __func__);
1854                 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s",
1855                     sshkey_type(ctx->old_keys[i]), fp);
1856                 free(fp);
1857         }
1858         if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1859                 if (get_saved_tio() != NULL) {
1860                         leave_raw_mode(1);
1861                         was_raw = 1;
1862                 }
1863                 response = NULL;
1864                 for (i = 0; !quit_pending && i < 3; i++) {
1865                         free(response);
1866                         response = read_passphrase("Accept updated hostkeys? "
1867                             "(yes/no): ", RP_ECHO);
1868                         if (strcasecmp(response, "yes") == 0)
1869                                 break;
1870                         else if (quit_pending || response == NULL ||
1871                             strcasecmp(response, "no") == 0) {
1872                                 options.update_hostkeys = 0;
1873                                 break;
1874                         } else {
1875                                 do_log2(loglevel, "Please enter "
1876                                     "\"yes\" or \"no\"");
1877                         }
1878                 }
1879                 if (quit_pending || i >= 3 || response == NULL)
1880                         options.update_hostkeys = 0;
1881                 free(response);
1882                 if (was_raw)
1883                         enter_raw_mode(1);
1884         }
1885
1886         /*
1887          * Now that all the keys are verified, we can go ahead and replace
1888          * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't
1889          * cancel the operation).
1890          */
1891         if (options.update_hostkeys != 0 &&
1892             (r = hostfile_replace_entries(options.user_hostfiles[0],
1893             ctx->host_str, ctx->ip_str, ctx->keys, ctx->nkeys,
1894             options.hash_known_hosts, 0,
1895             options.fingerprint_hash)) != 0)
1896                 error("%s: hostfile_replace_entries failed: %s",
1897                     __func__, ssh_err(r));
1898 }
1899
1900 static void
1901 client_global_hostkeys_private_confirm(struct ssh *ssh, int type,
1902     u_int32_t seq, void *_ctx)
1903 {
1904         struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx;
1905         size_t i, ndone;
1906         struct sshbuf *signdata;
1907         int r;
1908         const u_char *sig;
1909         size_t siglen;
1910
1911         if (ctx->nnew == 0)
1912                 fatal("%s: ctx->nnew == 0", __func__); /* sanity */
1913         if (type != SSH2_MSG_REQUEST_SUCCESS) {
1914                 error("Server failed to confirm ownership of "
1915                     "private host keys");
1916                 hostkeys_update_ctx_free(ctx);
1917                 return;
1918         }
1919         if ((signdata = sshbuf_new()) == NULL)
1920                 fatal("%s: sshbuf_new failed", __func__);
1921         /* Don't want to accidentally accept an unbound signature */
1922         if (ssh->kex->session_id_len == 0)
1923                 fatal("%s: ssh->kex->session_id_len == 0", __func__);
1924         /*
1925          * Expect a signature for each of the ctx->nnew private keys we
1926          * haven't seen before. They will be in the same order as the
1927          * ctx->keys where the corresponding ctx->keys_seen[i] == 0.
1928          */
1929         for (ndone = i = 0; i < ctx->nkeys; i++) {
1930                 if (ctx->keys_seen[i])
1931                         continue;
1932                 /* Prepare data to be signed: session ID, unique string, key */
1933                 sshbuf_reset(signdata);
1934                 if ( (r = sshbuf_put_cstring(signdata,
1935                     "hostkeys-prove-00@openssh.com")) != 0 ||
1936                     (r = sshbuf_put_string(signdata, ssh->kex->session_id,
1937                     ssh->kex->session_id_len)) != 0 ||
1938                     (r = sshkey_puts(ctx->keys[i], signdata)) != 0)
1939                         fatal("%s: failed to prepare signature: %s",
1940                             __func__, ssh_err(r));
1941                 /* Extract and verify signature */
1942                 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) {
1943                         error("%s: couldn't parse message: %s",
1944                             __func__, ssh_err(r));
1945                         goto out;
1946                 }
1947                 if ((r = sshkey_verify(ctx->keys[i], sig, siglen,
1948                     sshbuf_ptr(signdata), sshbuf_len(signdata), 0)) != 0) {
1949                         error("%s: server gave bad signature for %s key %zu",
1950                             __func__, sshkey_type(ctx->keys[i]), i);
1951                         goto out;
1952                 }
1953                 /* Key is good. Mark it as 'seen' */
1954                 ctx->keys_seen[i] = 2;
1955                 ndone++;
1956         }
1957         if (ndone != ctx->nnew)
1958                 fatal("%s: ndone != ctx->nnew (%zu / %zu)", __func__,
1959                     ndone, ctx->nnew);  /* Shouldn't happen */
1960         ssh_packet_check_eom(ssh);
1961
1962         /* Make the edits to known_hosts */
1963         update_known_hosts(ctx);
1964  out:
1965         hostkeys_update_ctx_free(ctx);
1966 }
1967
1968 /*
1969  * Returns non-zero if the key is accepted by HostkeyAlgorithms.
1970  * Made slightly less trivial by the multiple RSA signature algorithm names.
1971  */
1972 static int
1973 key_accepted_by_hostkeyalgs(const struct sshkey *key)
1974 {
1975         const char *ktype = sshkey_ssh_name(key);
1976         const char *hostkeyalgs = options.hostkeyalgorithms != NULL ?
1977             options.hostkeyalgorithms : KEX_DEFAULT_PK_ALG;
1978
1979         if (key == NULL || key->type == KEY_UNSPEC)
1980                 return 0;
1981         if (key->type == KEY_RSA &&
1982             (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 ||
1983             match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1))
1984                 return 1;
1985         return match_pattern_list(ktype, hostkeyalgs, 0) == 1;
1986 }
1987
1988 /*
1989  * Handle hostkeys-00@openssh.com global request to inform the client of all
1990  * the server's hostkeys. The keys are checked against the user's
1991  * HostkeyAlgorithms preference before they are accepted.
1992  */
1993 static int
1994 client_input_hostkeys(void)
1995 {
1996         struct ssh *ssh = active_state; /* XXX */
1997         const u_char *blob = NULL;
1998         size_t i, len = 0;
1999         struct sshbuf *buf = NULL;
2000         struct sshkey *key = NULL, **tmp;
2001         int r;
2002         char *fp;
2003         static int hostkeys_seen = 0; /* XXX use struct ssh */
2004         extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */
2005         struct hostkeys_update_ctx *ctx = NULL;
2006
2007         if (hostkeys_seen)
2008                 fatal("%s: server already sent hostkeys", __func__);
2009         if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK &&
2010             options.batch_mode)
2011                 return 1; /* won't ask in batchmode, so don't even try */
2012         if (!options.update_hostkeys || options.num_user_hostfiles <= 0)
2013                 return 1;
2014
2015         ctx = xcalloc(1, sizeof(*ctx));
2016         while (ssh_packet_remaining(ssh) > 0) {
2017                 sshkey_free(key);
2018                 key = NULL;
2019                 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) {
2020                         error("%s: couldn't parse message: %s",
2021                             __func__, ssh_err(r));
2022                         goto out;
2023                 }
2024                 if ((r = sshkey_from_blob(blob, len, &key)) != 0) {
2025                         error("%s: parse key: %s", __func__, ssh_err(r));
2026                         goto out;
2027                 }
2028                 fp = sshkey_fingerprint(key, options.fingerprint_hash,
2029                     SSH_FP_DEFAULT);
2030                 debug3("%s: received %s key %s", __func__,
2031                     sshkey_type(key), fp);
2032                 free(fp);
2033
2034                 if (!key_accepted_by_hostkeyalgs(key)) {
2035                         debug3("%s: %s key not permitted by HostkeyAlgorithms",
2036                             __func__, sshkey_ssh_name(key));
2037                         continue;
2038                 }
2039                 /* Skip certs */
2040                 if (sshkey_is_cert(key)) {
2041                         debug3("%s: %s key is a certificate; skipping",
2042                             __func__, sshkey_ssh_name(key));
2043                         continue;
2044                 }
2045                 /* Ensure keys are unique */
2046                 for (i = 0; i < ctx->nkeys; i++) {
2047                         if (sshkey_equal(key, ctx->keys[i])) {
2048                                 error("%s: received duplicated %s host key",
2049                                     __func__, sshkey_ssh_name(key));
2050                                 goto out;
2051                         }
2052                 }
2053                 /* Key is good, record it */
2054                 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1,
2055                     sizeof(*ctx->keys))) == NULL)
2056                         fatal("%s: recallocarray failed nkeys = %zu",
2057                             __func__, ctx->nkeys);
2058                 ctx->keys = tmp;
2059                 ctx->keys[ctx->nkeys++] = key;
2060                 key = NULL;
2061         }
2062
2063         if (ctx->nkeys == 0) {
2064                 debug("%s: server sent no hostkeys", __func__);
2065                 goto out;
2066         }
2067
2068         if ((ctx->keys_seen = calloc(ctx->nkeys,
2069             sizeof(*ctx->keys_seen))) == NULL)
2070                 fatal("%s: calloc failed", __func__);
2071
2072         get_hostfile_hostname_ipaddr(host,
2073             options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL,
2074             options.port, &ctx->host_str,
2075             options.check_host_ip ? &ctx->ip_str : NULL);
2076
2077         /* Find which keys we already know about. */
2078         if ((r = hostkeys_foreach(options.user_hostfiles[0], hostkeys_find,
2079             ctx, ctx->host_str, ctx->ip_str,
2080             HKF_WANT_PARSE_KEY|HKF_WANT_MATCH)) != 0) {
2081                 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r));
2082                 goto out;
2083         }
2084
2085         /* Figure out if we have any new keys to add */
2086         ctx->nnew = 0;
2087         for (i = 0; i < ctx->nkeys; i++) {
2088                 if (!ctx->keys_seen[i])
2089                         ctx->nnew++;
2090         }
2091
2092         debug3("%s: %zu keys from server: %zu new, %zu retained. %zu to remove",
2093             __func__, ctx->nkeys, ctx->nnew, ctx->nkeys - ctx->nnew, ctx->nold);
2094
2095         if (ctx->nnew == 0 && ctx->nold != 0) {
2096                 /* We have some keys to remove. Just do it. */
2097                 update_known_hosts(ctx);
2098         } else if (ctx->nnew != 0) {
2099                 /*
2100                  * We have received hitherto-unseen keys from the server.
2101                  * Ask the server to confirm ownership of the private halves.
2102                  */
2103                 debug3("%s: asking server to prove ownership for %zu keys",
2104                     __func__, ctx->nnew);
2105                 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
2106                     (r = sshpkt_put_cstring(ssh,
2107                     "hostkeys-prove-00@openssh.com")) != 0 ||
2108                     (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */
2109                         fatal("%s: cannot prepare packet: %s",
2110                             __func__, ssh_err(r));
2111                 if ((buf = sshbuf_new()) == NULL)
2112                         fatal("%s: sshbuf_new", __func__);
2113                 for (i = 0; i < ctx->nkeys; i++) {
2114                         if (ctx->keys_seen[i])
2115                                 continue;
2116                         sshbuf_reset(buf);
2117                         if ((r = sshkey_putb(ctx->keys[i], buf)) != 0)
2118                                 fatal("%s: sshkey_putb: %s",
2119                                     __func__, ssh_err(r));
2120                         if ((r = sshpkt_put_stringb(ssh, buf)) != 0)
2121                                 fatal("%s: sshpkt_put_string: %s",
2122                                     __func__, ssh_err(r));
2123                 }
2124                 if ((r = sshpkt_send(ssh)) != 0)
2125                         fatal("%s: sshpkt_send: %s", __func__, ssh_err(r));
2126                 client_register_global_confirm(
2127                     client_global_hostkeys_private_confirm, ctx);
2128                 ctx = NULL;  /* will be freed in callback */
2129         }
2130
2131         /* Success */
2132  out:
2133         hostkeys_update_ctx_free(ctx);
2134         sshkey_free(key);
2135         sshbuf_free(buf);
2136         /*
2137          * NB. Return success for all cases. The server doesn't need to know
2138          * what the client does with its hosts file.
2139          */
2140         return 1;
2141 }
2142
2143 static int
2144 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh)
2145 {
2146         char *rtype;
2147         int want_reply;
2148         int success = 0;
2149
2150         rtype = packet_get_cstring(NULL);
2151         want_reply = packet_get_char();
2152         debug("client_input_global_request: rtype %s want_reply %d",
2153             rtype, want_reply);
2154         if (strcmp(rtype, "hostkeys-00@openssh.com") == 0)
2155                 success = client_input_hostkeys();
2156         if (want_reply) {
2157                 packet_start(success ?
2158                     SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
2159                 packet_send();
2160                 packet_write_wait();
2161         }
2162         free(rtype);
2163         return 0;
2164 }
2165
2166 void
2167 client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem,
2168     const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env)
2169 {
2170         int len;
2171         Channel *c = NULL;
2172
2173         debug2("%s: id %d", __func__, id);
2174
2175         if ((c = channel_lookup(ssh, id)) == NULL)
2176                 fatal("%s: channel %d: unknown channel", __func__, id);
2177
2178         packet_set_interactive(want_tty,
2179             options.ip_qos_interactive, options.ip_qos_bulk);
2180
2181         if (want_tty) {
2182                 struct winsize ws;
2183
2184                 /* Store window size in the packet. */
2185                 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0)
2186                         memset(&ws, 0, sizeof(ws));
2187
2188                 channel_request_start(ssh, id, "pty-req", 1);
2189                 client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY);
2190                 packet_put_cstring(term != NULL ? term : "");
2191                 packet_put_int((u_int)ws.ws_col);
2192                 packet_put_int((u_int)ws.ws_row);
2193                 packet_put_int((u_int)ws.ws_xpixel);
2194                 packet_put_int((u_int)ws.ws_ypixel);
2195                 if (tiop == NULL)
2196                         tiop = get_saved_tio();
2197                 tty_make_modes(-1, tiop);
2198                 packet_send();
2199                 /* XXX wait for reply */
2200                 c->client_tty = 1;
2201         }
2202
2203         /* Transfer any environment variables from client to server */
2204         if (options.num_send_env != 0 && env != NULL) {
2205                 int i, j, matched;
2206                 char *name, *val;
2207
2208                 debug("Sending environment.");
2209                 for (i = 0; env[i] != NULL; i++) {
2210                         /* Split */
2211                         name = xstrdup(env[i]);
2212                         if ((val = strchr(name, '=')) == NULL) {
2213                                 free(name);
2214                                 continue;
2215                         }
2216                         *val++ = '\0';
2217
2218                         matched = 0;
2219                         for (j = 0; j < options.num_send_env; j++) {
2220                                 if (match_pattern(name, options.send_env[j])) {
2221                                         matched = 1;
2222                                         break;
2223                                 }
2224                         }
2225                         if (!matched) {
2226                                 debug3("Ignored env %s", name);
2227                                 free(name);
2228                                 continue;
2229                         }
2230
2231                         debug("Sending env %s = %s", name, val);
2232                         channel_request_start(ssh, id, "env", 0);
2233                         packet_put_cstring(name);
2234                         packet_put_cstring(val);
2235                         packet_send();
2236                         free(name);
2237                 }
2238         }
2239
2240         len = buffer_len(cmd);
2241         if (len > 0) {
2242                 if (len > 900)
2243                         len = 900;
2244                 if (want_subsystem) {
2245                         debug("Sending subsystem: %.*s",
2246                             len, (u_char*)buffer_ptr(cmd));
2247                         channel_request_start(ssh, id, "subsystem", 1);
2248                         client_expect_confirm(ssh, id, "subsystem",
2249                             CONFIRM_CLOSE);
2250                 } else {
2251                         debug("Sending command: %.*s",
2252                             len, (u_char*)buffer_ptr(cmd));
2253                         channel_request_start(ssh, id, "exec", 1);
2254                         client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE);
2255                 }
2256                 packet_put_string(buffer_ptr(cmd), buffer_len(cmd));
2257                 packet_send();
2258         } else {
2259                 channel_request_start(ssh, id, "shell", 1);
2260                 client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE);
2261                 packet_send();
2262         }
2263 }
2264
2265 static void
2266 client_init_dispatch(void)
2267 {
2268         dispatch_init(&dispatch_protocol_error);
2269
2270         dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
2271         dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
2272         dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
2273         dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
2274         dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
2275         dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
2276         dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
2277         dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
2278         dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
2279         dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm);
2280         dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm);
2281         dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);
2282
2283         /* rekeying */
2284         dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
2285
2286         /* global request reply messages */
2287         dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
2288         dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
2289 }
2290
2291 void
2292 client_stop_mux(void)
2293 {
2294         if (options.control_path != NULL && muxserver_sock != -1)
2295                 unlink(options.control_path);
2296         /*
2297          * If we are in persist mode, or don't have a shell, signal that we
2298          * should close when all active channels are closed.
2299          */
2300         if (options.control_persist || no_shell_flag) {
2301                 session_closed = 1;
2302                 setproctitle("[stopped mux]");
2303         }
2304 }
2305
2306 /* client specific fatal cleanup */
2307 void
2308 cleanup_exit(int i)
2309 {
2310         leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
2311         leave_non_blocking();
2312         if (options.control_path != NULL && muxserver_sock != -1)
2313                 unlink(options.control_path);
2314         ssh_kill_proxy_command();
2315         _exit(i);
2316 }