crypto/openssh/clientloop.c

   1 /* $OpenBSD: clientloop.c,v 1.318 2018/09/21 12:46:22 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 "sshbuf.h"
  95 #include "compat.h"
  96 #include "channels.h"
  97 #include "dispatch.h"
  98 #include "sshkey.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 struct sshbuf *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, struct sshbuf *);
 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 }
 214
 215 /*
 216  * Signal handler for signals that cause the program to terminate.  These
 217  * signals must be trapped to restore terminal modes.
 218  */
 219 /*ARGSUSED */
 220 static void
 221 signal_handler(int sig)
 222 {
 223         received_signal = sig;
 224         quit_pending = 1;
 225 }
 226
 227 /*
 228  * Sets control_persist_exit_time to the absolute time when the
 229  * backgrounded control master should exit due to expiry of the
 230  * ControlPersist timeout.  Sets it to 0 if we are not a backgrounded
 231  * control master process, or if there is no ControlPersist timeout.
 232  */
 233 static void
 234 set_control_persist_exit_time(struct ssh *ssh)
 235 {
 236         if (muxserver_sock == -1 || !options.control_persist
 237             || options.control_persist_timeout == 0) {
 238                 /* not using a ControlPersist timeout */
 239                 control_persist_exit_time = 0;
 240         } else if (channel_still_open(ssh)) {
 241                 /* some client connections are still open */
 242                 if (control_persist_exit_time > 0)
 243                         debug2("%s: cancel scheduled exit", __func__);
 244                 control_persist_exit_time = 0;
 245         } else if (control_persist_exit_time <= 0) {
 246                 /* a client connection has recently closed */
 247                 control_persist_exit_time = monotime() +
 248                         (time_t)options.control_persist_timeout;
 249                 debug2("%s: schedule exit in %d seconds", __func__,
 250                     options.control_persist_timeout);
 251         }
 252         /* else we are already counting down to the timeout */
 253 }
 254
 255 #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_"
 256 static int
 257 client_x11_display_valid(const char *display)
 258 {
 259         size_t i, dlen;
 260
 261         if (display == NULL)
 262                 return 0;
 263
 264         dlen = strlen(display);
 265         for (i = 0; i < dlen; i++) {
 266                 if (!isalnum((u_char)display[i]) &&
 267                     strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) {
 268                         debug("Invalid character '%c' in DISPLAY", display[i]);
 269                         return 0;
 270                 }
 271         }
 272         return 1;
 273 }
 274
 275 #define SSH_X11_PROTO           "MIT-MAGIC-COOKIE-1"
 276 #define X11_TIMEOUT_SLACK       60
 277 int
 278 client_x11_get_proto(struct ssh *ssh, const char *display,
 279     const char *xauth_path, u_int trusted, u_int timeout,
 280     char **_proto, char **_data)
 281 {
 282         char *cmd, line[512], xdisplay[512];
 283         char xauthfile[PATH_MAX], xauthdir[PATH_MAX];
 284         static char proto[512], data[512];
 285         FILE *f;
 286         int got_data = 0, generated = 0, do_unlink = 0, r;
 287         struct stat st;
 288         u_int now, x11_timeout_real;
 289
 290         *_proto = proto;
 291         *_data = data;
 292         proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0';
 293
 294         if (!client_x11_display_valid(display)) {
 295                 if (display != NULL)
 296                         logit("DISPLAY \"%s\" invalid; disabling X11 forwarding",
 297                             display);
 298                 return -1;
 299         }
 300         if (xauth_path != NULL && stat(xauth_path, &st) == -1) {
 301                 debug("No xauth program.");
 302                 xauth_path = NULL;
 303         }
 304
 305         if (xauth_path != NULL) {
 306                 /*
 307                  * Handle FamilyLocal case where $DISPLAY does
 308                  * not match an authorization entry.  For this we
 309                  * just try "xauth list unix:displaynum.screennum".
 310                  * XXX: "localhost" match to determine FamilyLocal
 311                  *      is not perfect.
 312                  */
 313                 if (strncmp(display, "localhost:", 10) == 0) {
 314                         if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s",
 315                             display + 10)) < 0 ||
 316                             (size_t)r >= sizeof(xdisplay)) {
 317                                 error("%s: display name too long", __func__);
 318                                 return -1;
 319                         }
 320                         display = xdisplay;
 321                 }
 322                 if (trusted == 0) {
 323                         /*
 324                          * Generate an untrusted X11 auth cookie.
 325                          *
 326                          * The authentication cookie should briefly outlive
 327                          * ssh's willingness to forward X11 connections to
 328                          * avoid nasty fail-open behaviour in the X server.
 329                          */
 330                         mktemp_proto(xauthdir, sizeof(xauthdir));
 331                         if (mkdtemp(xauthdir) == NULL) {
 332                                 error("%s: mkdtemp: %s",
 333                                     __func__, strerror(errno));
 334                                 return -1;
 335                         }
 336                         do_unlink = 1;
 337                         if ((r = snprintf(xauthfile, sizeof(xauthfile),
 338                             "%s/xauthfile", xauthdir)) < 0 ||
 339                             (size_t)r >= sizeof(xauthfile)) {
 340                                 error("%s: xauthfile path too long", __func__);
 341                                 unlink(xauthfile);
 342                                 rmdir(xauthdir);
 343                                 return -1;
 344                         }
 345
 346                         if (timeout == 0) {
 347                                 /* auth doesn't time out */
 348                                 xasprintf(&cmd, "%s -f %s generate %s %s "
 349                                     "untrusted 2>%s",
 350                                     xauth_path, xauthfile, display,
 351                                     SSH_X11_PROTO, _PATH_DEVNULL);
 352                         } else {
 353                                 /* Add some slack to requested expiry */
 354                                 if (timeout < UINT_MAX - X11_TIMEOUT_SLACK)
 355                                         x11_timeout_real = timeout +
 356                                             X11_TIMEOUT_SLACK;
 357                                 else {
 358                                         /* Don't overflow on long timeouts */
 359                                         x11_timeout_real = UINT_MAX;
 360                                 }
 361                                 xasprintf(&cmd, "%s -f %s generate %s %s "
 362                                     "untrusted timeout %u 2>%s",
 363                                     xauth_path, xauthfile, display,
 364                                     SSH_X11_PROTO, x11_timeout_real,
 365                                     _PATH_DEVNULL);
 366                         }
 367                         debug2("%s: %s", __func__, cmd);
 368
 369                         if (timeout != 0 && x11_refuse_time == 0) {
 370                                 now = monotime() + 1;
 371                                 if (UINT_MAX - timeout < now)
 372                                         x11_refuse_time = UINT_MAX;
 373                                 else
 374                                         x11_refuse_time = now + timeout;
 375                                 channel_set_x11_refuse_time(ssh,
 376                                     x11_refuse_time);
 377                         }
 378                         if (system(cmd) == 0)
 379                                 generated = 1;
 380                         free(cmd);
 381                 }
 382
 383                 /*
 384                  * When in untrusted mode, we read the cookie only if it was
 385                  * successfully generated as an untrusted one in the step
 386                  * above.
 387                  */
 388                 if (trusted || generated) {
 389                         xasprintf(&cmd,
 390                             "%s %s%s list %s 2>" _PATH_DEVNULL,
 391                             xauth_path,
 392                             generated ? "-f " : "" ,
 393                             generated ? xauthfile : "",
 394                             display);
 395                         debug2("x11_get_proto: %s", cmd);
 396                         f = popen(cmd, "r");
 397                         if (f && fgets(line, sizeof(line), f) &&
 398                             sscanf(line, "%*s %511s %511s", proto, data) == 2)
 399                                 got_data = 1;
 400                         if (f)
 401                                 pclose(f);
 402                         free(cmd);
 403                 }
 404         }
 405
 406         if (do_unlink) {
 407                 unlink(xauthfile);
 408                 rmdir(xauthdir);
 409         }
 410
 411         /* Don't fall back to fake X11 data for untrusted forwarding */
 412         if (!trusted && !got_data) {
 413                 error("Warning: untrusted X11 forwarding setup failed: "
 414                     "xauth key data not generated");
 415                 return -1;
 416         }
 417
 418         /*
 419          * If we didn't get authentication data, just make up some
 420          * data.  The forwarding code will check the validity of the
 421          * response anyway, and substitute this data.  The X11
 422          * server, however, will ignore this fake data and use
 423          * whatever authentication mechanisms it was using otherwise
 424          * for the local connection.
 425          */
 426         if (!got_data) {
 427                 u_int8_t rnd[16];
 428                 u_int i;
 429
 430                 logit("Warning: No xauth data; "
 431                     "using fake authentication data for X11 forwarding.");
 432                 strlcpy(proto, SSH_X11_PROTO, sizeof proto);
 433                 arc4random_buf(rnd, sizeof(rnd));
 434                 for (i = 0; i < sizeof(rnd); i++) {
 435                         snprintf(data + 2 * i, sizeof data - 2 * i, "%02x",
 436                             rnd[i]);
 437                 }
 438         }
 439
 440         return 0;
 441 }
 442
 443 /*
 444  * Checks if the client window has changed, and sends a packet about it to
 445  * the server if so.  The actual change is detected elsewhere (by a software
 446  * interrupt on Unix); this just checks the flag and sends a message if
 447  * appropriate.
 448  */
 449
 450 static void
 451 client_check_window_change(struct ssh *ssh)
 452 {
 453         if (!received_window_change_signal)
 454                 return;
 455         /** XXX race */
 456         received_window_change_signal = 0;
 457
 458         debug2("%s: changed", __func__);
 459
 460         channel_send_window_changes(ssh);
 461 }
 462
 463 static int
 464 client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh)
 465 {
 466         struct global_confirm *gc;
 467
 468         if ((gc = TAILQ_FIRST(&global_confirms)) == NULL)
 469                 return 0;
 470         if (gc->cb != NULL)
 471                 gc->cb(ssh, type, seq, gc->ctx);
 472         if (--gc->ref_count <= 0) {
 473                 TAILQ_REMOVE(&global_confirms, gc, entry);
 474                 explicit_bzero(gc, sizeof(*gc));
 475                 free(gc);
 476         }
 477
 478         packet_set_alive_timeouts(0);
 479         return 0;
 480 }
 481
 482 static void
 483 server_alive_check(void)
 484 {
 485         if (packet_inc_alive_timeouts() > options.server_alive_count_max) {
 486                 logit("Timeout, server %s not responding.", host);
 487                 cleanup_exit(255);
 488         }
 489         packet_start(SSH2_MSG_GLOBAL_REQUEST);
 490         packet_put_cstring("keepalive@openssh.com");
 491         packet_put_char(1);     /* boolean: want reply */
 492         packet_send();
 493         /* Insert an empty placeholder to maintain ordering */
 494         client_register_global_confirm(NULL, NULL);
 495 }
 496
 497 /*
 498  * Waits until the client can do something (some data becomes available on
 499  * one of the file descriptors).
 500  */
 501 static void
 502 client_wait_until_can_do_something(struct ssh *ssh,
 503     fd_set **readsetp, fd_set **writesetp,
 504     int *maxfdp, u_int *nallocp, int rekeying)
 505 {
 506         struct timeval tv, *tvp;
 507         int timeout_secs;
 508         time_t minwait_secs = 0, server_alive_time = 0, now = monotime();
 509         int r, ret;
 510
 511         /* Add any selections by the channel mechanism. */
 512         channel_prepare_select(active_state, readsetp, writesetp, maxfdp,
 513             nallocp, &minwait_secs);
 514
 515         /* channel_prepare_select could have closed the last channel */
 516         if (session_closed && !channel_still_open(ssh) &&
 517             !packet_have_data_to_write()) {
 518                 /* clear mask since we did not call select() */
 519                 memset(*readsetp, 0, *nallocp);
 520                 memset(*writesetp, 0, *nallocp);
 521                 return;
 522         }
 523
 524         FD_SET(connection_in, *readsetp);
 525
 526         /* Select server connection if have data to write to the server. */
 527         if (packet_have_data_to_write())
 528                 FD_SET(connection_out, *writesetp);
 529
 530         /*
 531          * Wait for something to happen.  This will suspend the process until
 532          * some selected descriptor can be read, written, or has some other
 533          * event pending, or a timeout expires.
 534          */
 535
 536         timeout_secs = INT_MAX; /* we use INT_MAX to mean no timeout */
 537         if (options.server_alive_interval > 0) {
 538                 timeout_secs = options.server_alive_interval;
 539                 server_alive_time = now + options.server_alive_interval;
 540         }
 541         if (options.rekey_interval > 0 && !rekeying)
 542                 timeout_secs = MINIMUM(timeout_secs, packet_get_rekey_timeout());
 543         set_control_persist_exit_time(ssh);
 544         if (control_persist_exit_time > 0) {
 545                 timeout_secs = MINIMUM(timeout_secs,
 546                         control_persist_exit_time - now);
 547                 if (timeout_secs < 0)
 548                         timeout_secs = 0;
 549         }
 550         if (minwait_secs != 0)
 551                 timeout_secs = MINIMUM(timeout_secs, (int)minwait_secs);
 552         if (timeout_secs == INT_MAX)
 553                 tvp = NULL;
 554         else {
 555                 tv.tv_sec = timeout_secs;
 556                 tv.tv_usec = 0;
 557                 tvp = &tv;
 558         }
 559
 560         ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
 561         if (ret < 0) {
 562                 /*
 563                  * We have to clear the select masks, because we return.
 564                  * We have to return, because the mainloop checks for the flags
 565                  * set by the signal handlers.
 566                  */
 567                 memset(*readsetp, 0, *nallocp);
 568                 memset(*writesetp, 0, *nallocp);
 569
 570                 if (errno == EINTR)
 571                         return;
 572                 /* Note: we might still have data in the buffers. */
 573                 if ((r = sshbuf_putf(stderr_buffer,
 574                     "select: %s\r\n", strerror(errno))) != 0)
 575                         fatal("%s: buffer error: %s", __func__, ssh_err(r));
 576                 quit_pending = 1;
 577         } else if (ret == 0) {
 578                 /*
 579                  * Timeout.  Could have been either keepalive or rekeying.
 580                  * Keepalive we check here, rekeying is checked in clientloop.
 581                  */
 582                 if (server_alive_time != 0 && server_alive_time <= monotime())
 583                         server_alive_check();
 584         }
 585
 586 }
 587
 588 static void
 589 client_suspend_self(struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr)
 590 {
 591         /* Flush stdout and stderr buffers. */
 592         if (sshbuf_len(bout) > 0)
 593                 atomicio(vwrite, fileno(stdout), sshbuf_mutable_ptr(bout),
 594                     sshbuf_len(bout));
 595         if (sshbuf_len(berr) > 0)
 596                 atomicio(vwrite, fileno(stderr), sshbuf_mutable_ptr(berr),
 597                     sshbuf_len(berr));
 598
 599         leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
 600
 601         sshbuf_reset(bin);
 602         sshbuf_reset(bout);
 603         sshbuf_reset(berr);
 604
 605         /* Send the suspend signal to the program itself. */
 606         kill(getpid(), SIGTSTP);
 607
 608         /* Reset window sizes in case they have changed */
 609         received_window_change_signal = 1;
 610
 611         enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
 612 }
 613
 614 static void
 615 client_process_net_input(fd_set *readset)
 616 {
 617         char buf[SSH_IOBUFSZ];
 618         int r, len;
 619
 620         /*
 621          * Read input from the server, and add any such data to the buffer of
 622          * the packet subsystem.
 623          */
 624         if (FD_ISSET(connection_in, readset)) {
 625                 /* Read as much as possible. */
 626                 len = read(connection_in, buf, sizeof(buf));
 627                 if (len == 0) {
 628                         /*
 629                          * Received EOF.  The remote host has closed the
 630                          * connection.
 631                          */
 632                         if ((r = sshbuf_putf(stderr_buffer,
 633                             "Connection to %.300s closed by remote host.\r\n",
 634                             host)) != 0)
 635                                 fatal("%s: buffer error: %s",
 636                                     __func__, ssh_err(r));
 637                         quit_pending = 1;
 638                         return;
 639                 }
 640                 /*
 641                  * There is a kernel bug on Solaris that causes select to
 642                  * sometimes wake up even though there is no data available.
 643                  */
 644                 if (len < 0 &&
 645                     (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
 646                         len = 0;
 647
 648                 if (len < 0) {
 649                         /*
 650                          * An error has encountered.  Perhaps there is a
 651                          * network problem.
 652                          */
 653                         if ((r = sshbuf_putf(stderr_buffer,
 654                             "Read from remote host %.300s: %.100s\r\n",
 655                             host, strerror(errno))) != 0)
 656                                 fatal("%s: buffer error: %s",
 657                                     __func__, ssh_err(r));
 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 r, 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 suppress 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                         if ((r = sshbuf_put(c->extended, errmsg,
 706                             strlen(errmsg))) != 0)
 707                                 fatal("%s: buffer error %s", __func__,
 708                                     ssh_err(r));
 709                 } else
 710                         error("%s", errmsg);
 711                 if (cr->action == CONFIRM_TTY) {
 712                         /*
 713                          * If a TTY allocation error occurred, then arrange
 714                          * for the correct TTY to leave raw mode.
 715                          */
 716                         if (c->self == session_ident)
 717                                 leave_raw_mode(0);
 718                         else
 719                                 mux_tty_alloc_failed(ssh, c);
 720                 } else if (cr->action == CONFIRM_CLOSE) {
 721                         chan_read_failed(ssh, c);
 722                         chan_write_failed(ssh, c);
 723                 }
 724         }
 725         free(cr);
 726 }
 727
 728 static void
 729 client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx)
 730 {
 731         free(ctx);
 732 }
 733
 734 void
 735 client_expect_confirm(struct ssh *ssh, int id, const char *request,
 736     enum confirm_action action)
 737 {
 738         struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr));
 739
 740         cr->request_type = request;
 741         cr->action = action;
 742
 743         channel_register_status_confirm(ssh, id, client_status_confirm,
 744             client_abandon_status_confirm, cr);
 745 }
 746
 747 void
 748 client_register_global_confirm(global_confirm_cb *cb, void *ctx)
 749 {
 750         struct global_confirm *gc, *last_gc;
 751
 752         /* Coalesce identical callbacks */
 753         last_gc = TAILQ_LAST(&global_confirms, global_confirms);
 754         if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) {
 755                 if (++last_gc->ref_count >= INT_MAX)
 756                         fatal("%s: last_gc->ref_count = %d",
 757                             __func__, last_gc->ref_count);
 758                 return;
 759         }
 760
 761         gc = xcalloc(1, sizeof(*gc));
 762         gc->cb = cb;
 763         gc->ctx = ctx;
 764         gc->ref_count = 1;
 765         TAILQ_INSERT_TAIL(&global_confirms, gc, entry);
 766 }
 767
 768 static void
 769 process_cmdline(struct ssh *ssh)
 770 {
 771         void (*handler)(int);
 772         char *s, *cmd;
 773         int ok, delete = 0, local = 0, remote = 0, dynamic = 0;
 774         struct Forward fwd;
 775
 776         memset(&fwd, 0, sizeof(fwd));
 777
 778         leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
 779         handler = signal(SIGINT, SIG_IGN);
 780         cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
 781         if (s == NULL)
 782                 goto out;
 783         while (isspace((u_char)*s))
 784                 s++;
 785         if (*s == '-')
 786                 s++;    /* Skip cmdline '-', if any */
 787         if (*s == '\0')
 788                 goto out;
 789
 790         if (*s == 'h' || *s == 'H' || *s == '?') {
 791                 logit("Commands:");
 792                 logit("      -L[bind_address:]port:host:hostport    "
 793                     "Request local forward");
 794                 logit("      -R[bind_address:]port:host:hostport    "
 795                     "Request remote forward");
 796                 logit("      -D[bind_address:]port                  "
 797                     "Request dynamic forward");
 798                 logit("      -KL[bind_address:]port                 "
 799                     "Cancel local forward");
 800                 logit("      -KR[bind_address:]port                 "
 801                     "Cancel remote forward");
 802                 logit("      -KD[bind_address:]port                 "
 803                     "Cancel dynamic forward");
 804                 if (!options.permit_local_command)
 805                         goto out;
 806                 logit("      !args                                  "
 807                     "Execute local command");
 808                 goto out;
 809         }
 810
 811         if (*s == '!' && options.permit_local_command) {
 812                 s++;
 813                 ssh_local_cmd(s);
 814                 goto out;
 815         }
 816
 817         if (*s == 'K') {
 818                 delete = 1;
 819                 s++;
 820         }
 821         if (*s == 'L')
 822                 local = 1;
 823         else if (*s == 'R')
 824                 remote = 1;
 825         else if (*s == 'D')
 826                 dynamic = 1;
 827         else {
 828                 logit("Invalid command.");
 829                 goto out;
 830         }
 831
 832         while (isspace((u_char)*++s))
 833                 ;
 834
 835         /* XXX update list of forwards in options */
 836         if (delete) {
 837                 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */
 838                 if (!parse_forward(&fwd, s, 1, 0)) {
 839                         logit("Bad forwarding close specification.");
 840                         goto out;
 841                 }
 842                 if (remote)
 843                         ok = channel_request_rforward_cancel(ssh, &fwd) == 0;
 844                 else if (dynamic)
 845                         ok = channel_cancel_lport_listener(ssh, &fwd,
 846                             0, &options.fwd_opts) > 0;
 847                 else
 848                         ok = channel_cancel_lport_listener(ssh, &fwd,
 849                             CHANNEL_CANCEL_PORT_STATIC,
 850                             &options.fwd_opts) > 0;
 851                 if (!ok) {
 852                         logit("Unknown port forwarding.");
 853                         goto out;
 854                 }
 855                 logit("Canceled forwarding.");
 856         } else {
 857                 if (!parse_forward(&fwd, s, dynamic, remote)) {
 858                         logit("Bad forwarding specification.");
 859                         goto out;
 860                 }
 861                 if (local || dynamic) {
 862                         if (!channel_setup_local_fwd_listener(ssh, &fwd,
 863                             &options.fwd_opts)) {
 864                                 logit("Port forwarding failed.");
 865                                 goto out;
 866                         }
 867                 } else {
 868                         if (channel_request_remote_forwarding(ssh, &fwd) < 0) {
 869                                 logit("Port forwarding failed.");
 870                                 goto out;
 871                         }
 872                 }
 873                 logit("Forwarding port.");
 874         }
 875
 876 out:
 877         signal(SIGINT, handler);
 878         enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
 879         free(cmd);
 880         free(fwd.listen_host);
 881         free(fwd.listen_path);
 882         free(fwd.connect_host);
 883         free(fwd.connect_path);
 884 }
 885
 886 /* reasons to suppress output of an escape command in help output */
 887 #define SUPPRESS_NEVER          0       /* never suppress, always show */
 888 #define SUPPRESS_MUXCLIENT      1       /* don't show in mux client sessions */
 889 #define SUPPRESS_MUXMASTER      2       /* don't show in mux master sessions */
 890 #define SUPPRESS_SYSLOG         4       /* don't show when logging to syslog */
 891 struct escape_help_text {
 892         const char *cmd;
 893         const char *text;
 894         unsigned int flags;
 895 };
 896 static struct escape_help_text esc_txt[] = {
 897     {".",  "terminate session", SUPPRESS_MUXMASTER},
 898     {".",  "terminate connection (and any multiplexed sessions)",
 899         SUPPRESS_MUXCLIENT},
 900     {"B",  "send a BREAK to the remote system", SUPPRESS_NEVER},
 901     {"C",  "open a command line", SUPPRESS_MUXCLIENT},
 902     {"R",  "request rekey", SUPPRESS_NEVER},
 903     {"V/v",  "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT},
 904     {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT},
 905     {"#",  "list forwarded connections", SUPPRESS_NEVER},
 906     {"&",  "background ssh (when waiting for connections to terminate)",
 907         SUPPRESS_MUXCLIENT},
 908     {"?", "this message", SUPPRESS_NEVER},
 909 };
 910
 911 static void
 912 print_escape_help(struct sshbuf *b, int escape_char, int mux_client,
 913     int using_stderr)
 914 {
 915         unsigned int i, suppress_flags;
 916         int r;
 917
 918         if ((r = sshbuf_putf(b,
 919             "%c?\r\nSupported escape sequences:\r\n", escape_char)) != 0)
 920                 fatal("%s: buffer error: %s", __func__, ssh_err(r));
 921
 922         suppress_flags =
 923             (mux_client ? SUPPRESS_MUXCLIENT : 0) |
 924             (mux_client ? 0 : SUPPRESS_MUXMASTER) |
 925             (using_stderr ? 0 : SUPPRESS_SYSLOG);
 926
 927         for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) {
 928                 if (esc_txt[i].flags & suppress_flags)
 929                         continue;
 930                 if ((r = sshbuf_putf(b, " %c%-3s - %s\r\n",
 931                     escape_char, esc_txt[i].cmd, esc_txt[i].text)) != 0)
 932                         fatal("%s: buffer error: %s", __func__, ssh_err(r));
 933         }
 934
 935         if ((r = sshbuf_putf(b,
 936             " %c%c   - send the escape character by typing it twice\r\n"
 937             "(Note that escapes are only recognized immediately after "
 938             "newline.)\r\n", escape_char, escape_char)) != 0)
 939                 fatal("%s: buffer error: %s", __func__, ssh_err(r));
 940 }
 941
 942 /*
 943  * Process the characters one by one.
 944  */
 945 static int
 946 process_escapes(struct ssh *ssh, Channel *c,
 947     struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr,
 948     char *buf, int len)
 949 {
 950         pid_t pid;
 951         int r, bytes = 0;
 952         u_int i;
 953         u_char ch;
 954         char *s;
 955         struct escape_filter_ctx *efc = c->filter_ctx == NULL ?
 956             NULL : (struct escape_filter_ctx *)c->filter_ctx;
 957
 958         if (c->filter_ctx == NULL)
 959                 return 0;
 960
 961         if (len <= 0)
 962                 return (0);
 963
 964         for (i = 0; i < (u_int)len; i++) {
 965                 /* Get one character at a time. */
 966                 ch = buf[i];
 967
 968                 if (efc->escape_pending) {
 969                         /* We have previously seen an escape character. */
 970                         /* Clear the flag now. */
 971                         efc->escape_pending = 0;
 972
 973                         /* Process the escaped character. */
 974                         switch (ch) {
 975                         case '.':
 976                                 /* Terminate the connection. */
 977                                 if ((r = sshbuf_putf(berr, "%c.\r\n",
 978                                     efc->escape_char)) != 0)
 979                                         fatal("%s: buffer error: %s",
 980                                             __func__, ssh_err(r));
 981                                 if (c && c->ctl_chan != -1) {
 982                                         chan_read_failed(ssh, c);
 983                                         chan_write_failed(ssh, c);
 984                                         if (c->detach_user) {
 985                                                 c->detach_user(ssh,
 986                                                     c->self, NULL);
 987                                         }
 988                                         c->type = SSH_CHANNEL_ABANDONED;
 989                                         sshbuf_reset(c->input);
 990                                         chan_ibuf_empty(ssh, c);
 991                                         return 0;
 992                                 } else
 993                                         quit_pending = 1;
 994                                 return -1;
 995
 996                         case 'Z' - 64:
 997                                 /* XXX support this for mux clients */
 998                                 if (c && c->ctl_chan != -1) {
 999                                         char b[16];
1000  noescape:
1001                                         if (ch == 'Z' - 64)
1002                                                 snprintf(b, sizeof b, "^Z");
1003                                         else
1004                                                 snprintf(b, sizeof b, "%c", ch);
1005                                         if ((r = sshbuf_putf(berr,
1006                                             "%c%s escape not available to "
1007                                             "multiplexed sessions\r\n",
1008                                             efc->escape_char, b)) != 0)
1009                                                 fatal("%s: buffer error: %s",
1010                                                     __func__, ssh_err(r));
1011                                         continue;
1012                                 }
1013                                 /* Suspend the program. Inform the user */
1014                                 if ((r = sshbuf_putf(berr,
1015                                     "%c^Z [suspend ssh]\r\n",
1016                                     efc->escape_char)) != 0)
1017                                         fatal("%s: buffer error: %s",
1018                                             __func__, ssh_err(r));
1019
1020                                 /* Restore terminal modes and suspend. */
1021                                 client_suspend_self(bin, bout, berr);
1022
1023                                 /* We have been continued. */
1024                                 continue;
1025
1026                         case 'B':
1027                                 if ((r = sshbuf_putf(berr,
1028                                     "%cB\r\n", efc->escape_char)) != 0)
1029                                         fatal("%s: buffer error: %s",
1030                                             __func__, ssh_err(r));
1031                                 channel_request_start(ssh, c->self, "break", 0);
1032                                 if ((r = sshpkt_put_u32(ssh, 1000)) != 0 ||
1033                                     (r = sshpkt_send(ssh)) != 0)
1034                                         fatal("%s: %s", __func__,
1035                                             ssh_err(r));
1036                                 continue;
1037
1038                         case 'R':
1039                                 if (datafellows & SSH_BUG_NOREKEY)
1040                                         logit("Server does not "
1041                                             "support re-keying");
1042                                 else
1043                                         need_rekeying = 1;
1044                                 continue;
1045
1046                         case 'V':
1047                                 /* FALLTHROUGH */
1048                         case 'v':
1049                                 if (c && c->ctl_chan != -1)
1050                                         goto noescape;
1051                                 if (!log_is_on_stderr()) {
1052                                         if ((r = sshbuf_putf(berr,
1053                                             "%c%c [Logging to syslog]\r\n",
1054                                             efc->escape_char, ch)) != 0)
1055                                                 fatal("%s: buffer error: %s",
1056                                                     __func__, ssh_err(r));
1057                                         continue;
1058                                 }
1059                                 if (ch == 'V' && options.log_level >
1060                                     SYSLOG_LEVEL_QUIET)
1061                                         log_change_level(--options.log_level);
1062                                 if (ch == 'v' && options.log_level <
1063                                     SYSLOG_LEVEL_DEBUG3)
1064                                         log_change_level(++options.log_level);
1065                                 if ((r = sshbuf_putf(berr,
1066                                     "%c%c [LogLevel %s]\r\n",
1067                                     efc->escape_char, ch,
1068                                     log_level_name(options.log_level))) != 0)
1069                                         fatal("%s: buffer error: %s",
1070                                             __func__, ssh_err(r));
1071                                 continue;
1072
1073                         case '&':
1074                                 if (c && c->ctl_chan != -1)
1075                                         goto noescape;
1076                                 /*
1077                                  * Detach the program (continue to serve
1078                                  * connections, but put in background and no
1079                                  * more new connections).
1080                                  */
1081                                 /* Restore tty modes. */
1082                                 leave_raw_mode(
1083                                     options.request_tty == REQUEST_TTY_FORCE);
1084
1085                                 /* Stop listening for new connections. */
1086                                 channel_stop_listening(ssh);
1087
1088                                 if ((r = sshbuf_putf(berr,
1089                                     "%c& [backgrounded]\n", efc->escape_char))
1090                                      != 0)
1091                                         fatal("%s: buffer error: %s",
1092                                             __func__, ssh_err(r));
1093
1094                                 /* Fork into background. */
1095                                 pid = fork();
1096                                 if (pid < 0) {
1097                                         error("fork: %.100s", strerror(errno));
1098                                         continue;
1099                                 }
1100                                 if (pid != 0) { /* This is the parent. */
1101                                         /* The parent just exits. */
1102                                         exit(0);
1103                                 }
1104                                 /* The child continues serving connections. */
1105                                 /* fake EOF on stdin */
1106                                 if ((r = sshbuf_put_u8(bin, 4)) != 0)
1107                                         fatal("%s: buffer error: %s",
1108                                             __func__, ssh_err(r));
1109                                 return -1;
1110                         case '?':
1111                                 print_escape_help(berr, efc->escape_char,
1112                                     (c && c->ctl_chan != -1),
1113                                     log_is_on_stderr());
1114                                 continue;
1115
1116                         case '#':
1117                                 if ((r = sshbuf_putf(berr, "%c#\r\n",
1118                                     efc->escape_char)) != 0)
1119                                         fatal("%s: buffer error: %s",
1120                                             __func__, ssh_err(r));
1121                                 s = channel_open_message(ssh);
1122                                 if ((r = sshbuf_put(berr, s, strlen(s))) != 0)
1123                                         fatal("%s: buffer error: %s",
1124                                             __func__, ssh_err(r));
1125                                 free(s);
1126                                 continue;
1127
1128                         case 'C':
1129                                 if (c && c->ctl_chan != -1)
1130                                         goto noescape;
1131                                 process_cmdline(ssh);
1132                                 continue;
1133
1134                         default:
1135                                 if (ch != efc->escape_char) {
1136                                         if ((r = sshbuf_put_u8(bin,
1137                                             efc->escape_char)) != 0)
1138                                                 fatal("%s: buffer error: %s",
1139                                                     __func__, ssh_err(r));
1140                                         bytes++;
1141                                 }
1142                                 /* Escaped characters fall through here */
1143                                 break;
1144                         }
1145                 } else {
1146                         /*
1147                          * The previous character was not an escape char.
1148                          * Check if this is an escape.
1149                          */
1150                         if (last_was_cr && ch == efc->escape_char) {
1151                                 /*
1152                                  * It is. Set the flag and continue to
1153                                  * next character.
1154                                  */
1155                                 efc->escape_pending = 1;
1156                                 continue;
1157                         }
1158                 }
1159
1160                 /*
1161                  * Normal character.  Record whether it was a newline,
1162                  * and append it to the buffer.
1163                  */
1164                 last_was_cr = (ch == '\r' || ch == '\n');
1165                 if ((r = sshbuf_put_u8(bin, ch)) != 0)
1166                         fatal("%s: buffer error: %s", __func__, ssh_err(r));
1167                 bytes++;
1168         }
1169         return bytes;
1170 }
1171
1172 /*
1173  * Get packets from the connection input buffer, and process them as long as
1174  * there are packets available.
1175  *
1176  * Any unknown packets received during the actual
1177  * session cause the session to terminate.  This is
1178  * intended to make debugging easier since no
1179  * confirmations are sent.  Any compatible protocol
1180  * extensions must be negotiated during the
1181  * preparatory phase.
1182  */
1183
1184 static void
1185 client_process_buffered_input_packets(void)
1186 {
1187         ssh_dispatch_run_fatal(active_state, DISPATCH_NONBLOCK, &quit_pending);
1188 }
1189
1190 /* scan buf[] for '~' before sending data to the peer */
1191
1192 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */
1193 void *
1194 client_new_escape_filter_ctx(int escape_char)
1195 {
1196         struct escape_filter_ctx *ret;
1197
1198         ret = xcalloc(1, sizeof(*ret));
1199         ret->escape_pending = 0;
1200         ret->escape_char = escape_char;
1201         return (void *)ret;
1202 }
1203
1204 /* Free the escape filter context on channel free */
1205 void
1206 client_filter_cleanup(struct ssh *ssh, int cid, void *ctx)
1207 {
1208         free(ctx);
1209 }
1210
1211 int
1212 client_simple_escape_filter(struct ssh *ssh, Channel *c, char *buf, int len)
1213 {
1214         if (c->extended_usage != CHAN_EXTENDED_WRITE)
1215                 return 0;
1216
1217         return process_escapes(ssh, c, c->input, c->output, c->extended,
1218             buf, len);
1219 }
1220
1221 static void
1222 client_channel_closed(struct ssh *ssh, int id, void *arg)
1223 {
1224         channel_cancel_cleanup(ssh, id);
1225         session_closed = 1;
1226         leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1227 }
1228
1229 /*
1230  * Implements the interactive session with the server.  This is called after
1231  * the user has been authenticated, and a command has been started on the
1232  * remote host.  If escape_char != SSH_ESCAPECHAR_NONE, it is the character
1233  * used as an escape character for terminating or suspending the session.
1234  */
1235 int
1236 client_loop(struct ssh *ssh, int have_pty, int escape_char_arg,
1237     int ssh2_chan_id)
1238 {
1239         fd_set *readset = NULL, *writeset = NULL;
1240         double start_time, total_time;
1241         int r, max_fd = 0, max_fd2 = 0, len;
1242         u_int64_t ibytes, obytes;
1243         u_int nalloc = 0;
1244         char buf[100];
1245
1246         debug("Entering interactive session.");
1247
1248         if (options.control_master &&
1249             !option_clear_or_none(options.control_path)) {
1250                 debug("pledge: id");
1251                 if (pledge("stdio rpath wpath cpath unix inet dns recvfd proc exec id tty",
1252                     NULL) == -1)
1253                         fatal("%s pledge(): %s", __func__, strerror(errno));
1254
1255         } else if (options.forward_x11 || options.permit_local_command) {
1256                 debug("pledge: exec");
1257                 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty",
1258                     NULL) == -1)
1259                         fatal("%s pledge(): %s", __func__, strerror(errno));
1260
1261         } else if (options.update_hostkeys) {
1262                 debug("pledge: filesystem full");
1263                 if (pledge("stdio rpath wpath cpath unix inet dns proc tty",
1264                     NULL) == -1)
1265                         fatal("%s pledge(): %s", __func__, strerror(errno));
1266
1267         } else if (!option_clear_or_none(options.proxy_command) ||
1268             fork_after_authentication_flag) {
1269                 debug("pledge: proc");
1270                 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1)
1271                         fatal("%s pledge(): %s", __func__, strerror(errno));
1272
1273         } else {
1274                 debug("pledge: network");
1275                 if (pledge("stdio unix inet dns proc tty", NULL) == -1)
1276                         fatal("%s pledge(): %s", __func__, strerror(errno));
1277         }
1278
1279         start_time = monotime_double();
1280
1281         /* Initialize variables. */
1282         last_was_cr = 1;
1283         exit_status = -1;
1284         connection_in = packet_get_connection_in();
1285         connection_out = packet_get_connection_out();
1286         max_fd = MAXIMUM(connection_in, connection_out);
1287
1288         quit_pending = 0;
1289
1290         /* Initialize buffer. */
1291         if ((stderr_buffer = sshbuf_new()) == NULL)
1292                 fatal("%s: sshbuf_new failed", __func__);
1293
1294         client_init_dispatch();
1295
1296         /*
1297          * Set signal handlers, (e.g. to restore non-blocking mode)
1298          * but don't overwrite SIG_IGN, matches behaviour from rsh(1)
1299          */
1300         if (signal(SIGHUP, SIG_IGN) != SIG_IGN)
1301                 signal(SIGHUP, signal_handler);
1302         if (signal(SIGINT, SIG_IGN) != SIG_IGN)
1303                 signal(SIGINT, signal_handler);
1304         if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
1305                 signal(SIGQUIT, signal_handler);
1306         if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
1307                 signal(SIGTERM, signal_handler);
1308         signal(SIGWINCH, window_change_handler);
1309
1310         if (have_pty)
1311                 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1312
1313         session_ident = ssh2_chan_id;
1314         if (session_ident != -1) {
1315                 if (escape_char_arg != SSH_ESCAPECHAR_NONE) {
1316                         channel_register_filter(ssh, session_ident,
1317                             client_simple_escape_filter, NULL,
1318                             client_filter_cleanup,
1319                             client_new_escape_filter_ctx(
1320                             escape_char_arg));
1321                 }
1322                 channel_register_cleanup(ssh, session_ident,
1323                     client_channel_closed, 0);
1324         }
1325
1326         /* Main loop of the client for the interactive session mode. */
1327         while (!quit_pending) {
1328
1329                 /* Process buffered packets sent by the server. */
1330                 client_process_buffered_input_packets();
1331
1332                 if (session_closed && !channel_still_open(ssh))
1333                         break;
1334
1335                 if (ssh_packet_is_rekeying(ssh)) {
1336                         debug("rekeying in progress");
1337                 } else if (need_rekeying) {
1338                         /* manual rekey request */
1339                         debug("need rekeying");
1340                         if ((r = kex_start_rekex(ssh)) != 0)
1341                                 fatal("%s: kex_start_rekex: %s", __func__,
1342                                     ssh_err(r));
1343                         need_rekeying = 0;
1344                 } else {
1345                         /*
1346                          * Make packets from buffered channel data, and
1347                          * enqueue them for sending to the server.
1348                          */
1349                         if (packet_not_very_much_data_to_write())
1350                                 channel_output_poll(ssh);
1351
1352                         /*
1353                          * Check if the window size has changed, and buffer a
1354                          * message about it to the server if so.
1355                          */
1356                         client_check_window_change(ssh);
1357
1358                         if (quit_pending)
1359                                 break;
1360                 }
1361                 /*
1362                  * Wait until we have something to do (something becomes
1363                  * available on one of the descriptors).
1364                  */
1365                 max_fd2 = max_fd;
1366                 client_wait_until_can_do_something(ssh, &readset, &writeset,
1367                     &max_fd2, &nalloc, ssh_packet_is_rekeying(ssh));
1368
1369                 if (quit_pending)
1370                         break;
1371
1372                 /* Do channel operations unless rekeying in progress. */
1373                 if (!ssh_packet_is_rekeying(ssh))
1374                         channel_after_select(ssh, readset, writeset);
1375
1376                 /* Buffer input from the connection.  */
1377                 client_process_net_input(readset);
1378
1379                 if (quit_pending)
1380                         break;
1381
1382                 /*
1383                  * Send as much buffered packet data as possible to the
1384                  * sender.
1385                  */
1386                 if (FD_ISSET(connection_out, writeset))
1387                         packet_write_poll();
1388
1389                 /*
1390                  * If we are a backgrounded control master, and the
1391                  * timeout has expired without any active client
1392                  * connections, then quit.
1393                  */
1394                 if (control_persist_exit_time > 0) {
1395                         if (monotime() >= control_persist_exit_time) {
1396                                 debug("ControlPersist timeout expired");
1397                                 break;
1398                         }
1399                 }
1400         }
1401         free(readset);
1402         free(writeset);
1403
1404         /* Terminate the session. */
1405
1406         /* Stop watching for window change. */
1407         signal(SIGWINCH, SIG_DFL);
1408
1409         packet_start(SSH2_MSG_DISCONNECT);
1410         packet_put_int(SSH2_DISCONNECT_BY_APPLICATION);
1411         packet_put_cstring("disconnected by user");
1412         packet_put_cstring(""); /* language tag */
1413         packet_send();
1414         packet_write_wait();
1415
1416         channel_free_all(ssh);
1417
1418         if (have_pty)
1419                 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1420
1421         /* restore blocking io */
1422         if (!isatty(fileno(stdin)))
1423                 unset_nonblock(fileno(stdin));
1424         if (!isatty(fileno(stdout)))
1425                 unset_nonblock(fileno(stdout));
1426         if (!isatty(fileno(stderr)))
1427                 unset_nonblock(fileno(stderr));
1428
1429         /*
1430          * If there was no shell or command requested, there will be no remote
1431          * exit status to be returned.  In that case, clear error code if the
1432          * connection was deliberately terminated at this end.
1433          */
1434         if (no_shell_flag && received_signal == SIGTERM) {
1435                 received_signal = 0;
1436                 exit_status = 0;
1437         }
1438
1439         if (received_signal) {
1440                 verbose("Killed by signal %d.", (int) received_signal);
1441                 cleanup_exit(0);
1442         }
1443
1444         /*
1445          * In interactive mode (with pseudo tty) display a message indicating
1446          * that the connection has been closed.
1447          */
1448         if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
1449                 if ((r = sshbuf_putf(stderr_buffer,
1450                     "Connection to %.64s closed.\r\n", host)) != 0)
1451                         fatal("%s: buffer error: %s", __func__, ssh_err(r));
1452         }
1453
1454         /* Output any buffered data for stderr. */
1455         if (sshbuf_len(stderr_buffer) > 0) {
1456                 len = atomicio(vwrite, fileno(stderr),
1457                     (u_char *)sshbuf_ptr(stderr_buffer),
1458                     sshbuf_len(stderr_buffer));
1459                 if (len < 0 || (u_int)len != sshbuf_len(stderr_buffer))
1460                         error("Write failed flushing stderr buffer.");
1461                 else if ((r = sshbuf_consume(stderr_buffer, len)) != 0)
1462                         fatal("%s: buffer error: %s", __func__, ssh_err(r));
1463         }
1464
1465         /* Clear and free any buffers. */
1466         explicit_bzero(buf, sizeof(buf));
1467         sshbuf_free(stderr_buffer);
1468
1469         /* Report bytes transferred, and transfer rates. */
1470         total_time = monotime_double() - start_time;
1471         packet_get_bytes(&ibytes, &obytes);
1472         verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds",
1473             (unsigned long long)obytes, (unsigned long long)ibytes, total_time);
1474         if (total_time > 0)
1475                 verbose("Bytes per second: sent %.1f, received %.1f",
1476                     obytes / total_time, ibytes / total_time);
1477         /* Return the exit status of the program. */
1478         debug("Exit status %d", exit_status);
1479         return exit_status;
1480 }
1481
1482 /*********/
1483
1484 static Channel *
1485 client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type,
1486     int rchan, u_int rwindow, u_int rmaxpack)
1487 {
1488         Channel *c = NULL;
1489         struct sshbuf *b = NULL;
1490         char *listen_address, *originator_address;
1491         u_short listen_port, originator_port;
1492         int r;
1493
1494         /* Get rest of the packet */
1495         listen_address = packet_get_string(NULL);
1496         listen_port = packet_get_int();
1497         originator_address = packet_get_string(NULL);
1498         originator_port = packet_get_int();
1499         packet_check_eom();
1500
1501         debug("%s: listen %s port %d, originator %s port %d", __func__,
1502             listen_address, listen_port, originator_address, originator_port);
1503
1504         c = channel_connect_by_listen_address(ssh, listen_address, listen_port,
1505             "forwarded-tcpip", originator_address);
1506
1507         if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) {
1508                 if ((b = sshbuf_new()) == NULL) {
1509                         error("%s: alloc reply", __func__);
1510                         goto out;
1511                 }
1512                 /* reconstruct and send to muxclient */
1513                 if ((r = sshbuf_put_u8(b, 0)) != 0 ||   /* padlen */
1514                     (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 ||
1515                     (r = sshbuf_put_cstring(b, request_type)) != 0 ||
1516                     (r = sshbuf_put_u32(b, rchan)) != 0 ||
1517                     (r = sshbuf_put_u32(b, rwindow)) != 0 ||
1518                     (r = sshbuf_put_u32(b, rmaxpack)) != 0 ||
1519                     (r = sshbuf_put_cstring(b, listen_address)) != 0 ||
1520                     (r = sshbuf_put_u32(b, listen_port)) != 0 ||
1521                     (r = sshbuf_put_cstring(b, originator_address)) != 0 ||
1522                     (r = sshbuf_put_u32(b, originator_port)) != 0 ||
1523                     (r = sshbuf_put_stringb(c->output, b)) != 0) {
1524                         error("%s: compose for muxclient %s", __func__,
1525                             ssh_err(r));
1526                         goto out;
1527                 }
1528         }
1529
1530  out:
1531         sshbuf_free(b);
1532         free(originator_address);
1533         free(listen_address);
1534         return c;
1535 }
1536
1537 static Channel *
1538 client_request_forwarded_streamlocal(struct ssh *ssh,
1539     const char *request_type, int rchan)
1540 {
1541         Channel *c = NULL;
1542         char *listen_path;
1543
1544         /* Get the remote path. */
1545         listen_path = packet_get_string(NULL);
1546         /* XXX: Skip reserved field for now. */
1547         if (packet_get_string_ptr(NULL) == NULL)
1548                 fatal("%s: packet_get_string_ptr failed", __func__);
1549         packet_check_eom();
1550
1551         debug("%s: %s", __func__, listen_path);
1552
1553         c = channel_connect_by_listen_path(ssh, listen_path,
1554             "forwarded-streamlocal@openssh.com", "forwarded-streamlocal");
1555         free(listen_path);
1556         return c;
1557 }
1558
1559 static Channel *
1560 client_request_x11(struct ssh *ssh, const char *request_type, int rchan)
1561 {
1562         Channel *c = NULL;
1563         char *originator;
1564         u_short originator_port;
1565         int sock;
1566
1567         if (!options.forward_x11) {
1568                 error("Warning: ssh server tried X11 forwarding.");
1569                 error("Warning: this is probably a break-in attempt by a "
1570                     "malicious server.");
1571                 return NULL;
1572         }
1573         if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) {
1574                 verbose("Rejected X11 connection after ForwardX11Timeout "
1575                     "expired");
1576                 return NULL;
1577         }
1578         originator = packet_get_string(NULL);
1579         originator_port = packet_get_int();
1580         packet_check_eom();
1581         /* XXX check permission */
1582         debug("client_request_x11: request from %s %d", originator,
1583             originator_port);
1584         free(originator);
1585         sock = x11_connect_display(ssh);
1586         if (sock < 0)
1587                 return NULL;
1588         c = channel_new(ssh, "x11",
1589             SSH_CHANNEL_X11_OPEN, sock, sock, -1,
1590             CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1);
1591         c->force_drain = 1;
1592         return c;
1593 }
1594
1595 static Channel *
1596 client_request_agent(struct ssh *ssh, const char *request_type, int rchan)
1597 {
1598         Channel *c = NULL;
1599         int r, sock;
1600
1601         if (!options.forward_agent) {
1602                 error("Warning: ssh server tried agent forwarding.");
1603                 error("Warning: this is probably a break-in attempt by a "
1604                     "malicious server.");
1605                 return NULL;
1606         }
1607         if ((r = ssh_get_authentication_socket(&sock)) != 0) {
1608                 if (r != SSH_ERR_AGENT_NOT_PRESENT)
1609                         debug("%s: ssh_get_authentication_socket: %s",
1610                             __func__, ssh_err(r));
1611                 return NULL;
1612         }
1613         c = channel_new(ssh, "authentication agent connection",
1614             SSH_CHANNEL_OPEN, sock, sock, -1,
1615             CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0,
1616             "authentication agent connection", 1);
1617         c->force_drain = 1;
1618         return c;
1619 }
1620
1621 char *
1622 client_request_tun_fwd(struct ssh *ssh, int tun_mode,
1623     int local_tun, int remote_tun)
1624 {
1625         Channel *c;
1626         int fd;
1627         char *ifname = NULL;
1628
1629         if (tun_mode == SSH_TUNMODE_NO)
1630                 return 0;
1631
1632         debug("Requesting tun unit %d in mode %d", local_tun, tun_mode);
1633
1634         /* Open local tunnel device */
1635         if ((fd = tun_open(local_tun, tun_mode, &ifname)) == -1) {
1636                 error("Tunnel device open failed.");
1637                 return NULL;
1638         }
1639         debug("Tunnel forwarding using interface %s", ifname);
1640
1641         c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1,
1642             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1643         c->datagram = 1;
1644
1645 #if defined(SSH_TUN_FILTER)
1646         if (options.tun_open == SSH_TUNMODE_POINTOPOINT)
1647                 channel_register_filter(ssh, c->self, sys_tun_infilter,
1648                     sys_tun_outfilter, NULL, NULL);
1649 #endif
1650
1651         packet_start(SSH2_MSG_CHANNEL_OPEN);
1652         packet_put_cstring("tun@openssh.com");
1653         packet_put_int(c->self);
1654         packet_put_int(c->local_window_max);
1655         packet_put_int(c->local_maxpacket);
1656         packet_put_int(tun_mode);
1657         packet_put_int(remote_tun);
1658         packet_send();
1659
1660         return ifname;
1661 }
1662
1663 /* XXXX move to generic input handler */
1664 static int
1665 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh)
1666 {
1667         Channel *c = NULL;
1668         char *ctype;
1669         int rchan;
1670         u_int rmaxpack, rwindow, len;
1671
1672         ctype = packet_get_string(&len);
1673         rchan = packet_get_int();
1674         rwindow = packet_get_int();
1675         rmaxpack = packet_get_int();
1676
1677         debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
1678             ctype, rchan, rwindow, rmaxpack);
1679
1680         if (strcmp(ctype, "forwarded-tcpip") == 0) {
1681                 c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow,
1682                     rmaxpack);
1683         } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) {
1684                 c = client_request_forwarded_streamlocal(ssh, ctype, rchan);
1685         } else if (strcmp(ctype, "x11") == 0) {
1686                 c = client_request_x11(ssh, ctype, rchan);
1687         } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) {
1688                 c = client_request_agent(ssh, ctype, rchan);
1689         }
1690         if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) {
1691                 debug3("proxied to downstream: %s", ctype);
1692         } else if (c != NULL) {
1693                 debug("confirm %s", ctype);
1694                 c->remote_id = rchan;
1695                 c->have_remote_id = 1;
1696                 c->remote_window = rwindow;
1697                 c->remote_maxpacket = rmaxpack;
1698                 if (c->type != SSH_CHANNEL_CONNECTING) {
1699                         packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1700                         packet_put_int(c->remote_id);
1701                         packet_put_int(c->self);
1702                         packet_put_int(c->local_window);
1703                         packet_put_int(c->local_maxpacket);
1704                         packet_send();
1705                 }
1706         } else {
1707                 debug("failure %s", ctype);
1708                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1709                 packet_put_int(rchan);
1710                 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1711                 packet_put_cstring("open failed");
1712                 packet_put_cstring("");
1713                 packet_send();
1714         }
1715         free(ctype);
1716         return 0;
1717 }
1718
1719 static int
1720 client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh)
1721 {
1722         Channel *c = NULL;
1723         int exitval, id, reply, success = 0;
1724         char *rtype;
1725
1726         id = packet_get_int();
1727         c = channel_lookup(ssh, id);
1728         if (channel_proxy_upstream(c, type, seq, ssh))
1729                 return 0;
1730         rtype = packet_get_string(NULL);
1731         reply = packet_get_char();
1732
1733         debug("client_input_channel_req: channel %d rtype %s reply %d",
1734             id, rtype, reply);
1735
1736         if (id == -1) {
1737                 error("client_input_channel_req: request for channel -1");
1738         } else if (c == NULL) {
1739                 error("client_input_channel_req: channel %d: "
1740                     "unknown channel", id);
1741         } else if (strcmp(rtype, "eow@openssh.com") == 0) {
1742                 packet_check_eom();
1743                 chan_rcvd_eow(ssh, c);
1744         } else if (strcmp(rtype, "exit-status") == 0) {
1745                 exitval = packet_get_int();
1746                 if (c->ctl_chan != -1) {
1747                         mux_exit_message(ssh, c, exitval);
1748                         success = 1;
1749                 } else if (id == session_ident) {
1750                         /* Record exit value of local session */
1751                         success = 1;
1752                         exit_status = exitval;
1753                 } else {
1754                         /* Probably for a mux channel that has already closed */
1755                         debug("%s: no sink for exit-status on channel %d",
1756                             __func__, id);
1757                 }
1758                 packet_check_eom();
1759         }
1760         if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) {
1761                 if (!c->have_remote_id)
1762                         fatal("%s: channel %d: no remote_id",
1763                             __func__, c->self);
1764                 packet_start(success ?
1765                     SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1766                 packet_put_int(c->remote_id);
1767                 packet_send();
1768         }
1769         free(rtype);
1770         return 0;
1771 }
1772
1773 struct hostkeys_update_ctx {
1774         /* The hostname and (optionally) IP address string for the server */
1775         char *host_str, *ip_str;
1776
1777         /*
1778          * Keys received from the server and a flag for each indicating
1779          * whether they already exist in known_hosts.
1780          * keys_seen is filled in by hostkeys_find() and later (for new
1781          * keys) by client_global_hostkeys_private_confirm().
1782          */
1783         struct sshkey **keys;
1784         int *keys_seen;
1785         size_t nkeys, nnew;
1786
1787         /*
1788          * Keys that are in known_hosts, but were not present in the update
1789          * from the server (i.e. scheduled to be deleted).
1790          * Filled in by hostkeys_find().
1791          */
1792         struct sshkey **old_keys;
1793         size_t nold;
1794 };
1795
1796 static void
1797 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx)
1798 {
1799         size_t i;
1800
1801         if (ctx == NULL)
1802                 return;
1803         for (i = 0; i < ctx->nkeys; i++)
1804                 sshkey_free(ctx->keys[i]);
1805         free(ctx->keys);
1806         free(ctx->keys_seen);
1807         for (i = 0; i < ctx->nold; i++)
1808                 sshkey_free(ctx->old_keys[i]);
1809         free(ctx->old_keys);
1810         free(ctx->host_str);
1811         free(ctx->ip_str);
1812         free(ctx);
1813 }
1814
1815 static int
1816 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx)
1817 {
1818         struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx;
1819         size_t i;
1820         struct sshkey **tmp;
1821
1822         if (l->status != HKF_STATUS_MATCHED || l->key == NULL)
1823                 return 0;
1824
1825         /* Mark off keys we've already seen for this host */
1826         for (i = 0; i < ctx->nkeys; i++) {
1827                 if (sshkey_equal(l->key, ctx->keys[i])) {
1828                         debug3("%s: found %s key at %s:%ld", __func__,
1829                             sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum);
1830                         ctx->keys_seen[i] = 1;
1831                         return 0;
1832                 }
1833         }
1834         /* This line contained a key that not offered by the server */
1835         debug3("%s: deprecated %s key at %s:%ld", __func__,
1836             sshkey_ssh_name(l->key), l->path, l->linenum);
1837         if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1,
1838             sizeof(*ctx->old_keys))) == NULL)
1839                 fatal("%s: recallocarray failed nold = %zu",
1840                     __func__, ctx->nold);
1841         ctx->old_keys = tmp;
1842         ctx->old_keys[ctx->nold++] = l->key;
1843         l->key = NULL;
1844
1845         return 0;
1846 }
1847
1848 static void
1849 update_known_hosts(struct hostkeys_update_ctx *ctx)
1850 {
1851         int r, was_raw = 0;
1852         int loglevel = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK ?
1853             SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE;
1854         char *fp, *response;
1855         size_t i;
1856
1857         for (i = 0; i < ctx->nkeys; i++) {
1858                 if (ctx->keys_seen[i] != 2)
1859                         continue;
1860                 if ((fp = sshkey_fingerprint(ctx->keys[i],
1861                     options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
1862                         fatal("%s: sshkey_fingerprint failed", __func__);
1863                 do_log2(loglevel, "Learned new hostkey: %s %s",
1864                     sshkey_type(ctx->keys[i]), fp);
1865                 free(fp);
1866         }
1867         for (i = 0; i < ctx->nold; i++) {
1868                 if ((fp = sshkey_fingerprint(ctx->old_keys[i],
1869                     options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
1870                         fatal("%s: sshkey_fingerprint failed", __func__);
1871                 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s",
1872                     sshkey_type(ctx->old_keys[i]), fp);
1873                 free(fp);
1874         }
1875         if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1876                 if (get_saved_tio() != NULL) {
1877                         leave_raw_mode(1);
1878                         was_raw = 1;
1879                 }
1880                 response = NULL;
1881                 for (i = 0; !quit_pending && i < 3; i++) {
1882                         free(response);
1883                         response = read_passphrase("Accept updated hostkeys? "
1884                             "(yes/no): ", RP_ECHO);
1885                         if (strcasecmp(response, "yes") == 0)
1886                                 break;
1887                         else if (quit_pending || response == NULL ||
1888                             strcasecmp(response, "no") == 0) {
1889                                 options.update_hostkeys = 0;
1890                                 break;
1891                         } else {
1892                                 do_log2(loglevel, "Please enter "
1893                                     "\"yes\" or \"no\"");
1894                         }
1895                 }
1896                 if (quit_pending || i >= 3 || response == NULL)
1897                         options.update_hostkeys = 0;
1898                 free(response);
1899                 if (was_raw)
1900                         enter_raw_mode(1);
1901         }
1902
1903         /*
1904          * Now that all the keys are verified, we can go ahead and replace
1905          * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't
1906          * cancel the operation).
1907          */
1908         if (options.update_hostkeys != 0 &&
1909             (r = hostfile_replace_entries(options.user_hostfiles[0],
1910             ctx->host_str, ctx->ip_str, ctx->keys, ctx->nkeys,
1911             options.hash_known_hosts, 0,
1912             options.fingerprint_hash)) != 0)
1913                 error("%s: hostfile_replace_entries failed: %s",
1914                     __func__, ssh_err(r));
1915 }
1916
1917 static void
1918 client_global_hostkeys_private_confirm(struct ssh *ssh, int type,
1919     u_int32_t seq, void *_ctx)
1920 {
1921         struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx;
1922         size_t i, ndone;
1923         struct sshbuf *signdata;
1924         int r, kexsigtype, use_kexsigtype;
1925         const u_char *sig;
1926         size_t siglen;
1927
1928         if (ctx->nnew == 0)
1929                 fatal("%s: ctx->nnew == 0", __func__); /* sanity */
1930         if (type != SSH2_MSG_REQUEST_SUCCESS) {
1931                 error("Server failed to confirm ownership of "
1932                     "private host keys");
1933                 hostkeys_update_ctx_free(ctx);
1934                 return;
1935         }
1936         kexsigtype = sshkey_type_plain(
1937             sshkey_type_from_name(ssh->kex->hostkey_alg));
1938
1939         if ((signdata = sshbuf_new()) == NULL)
1940                 fatal("%s: sshbuf_new failed", __func__);
1941         /* Don't want to accidentally accept an unbound signature */
1942         if (ssh->kex->session_id_len == 0)
1943                 fatal("%s: ssh->kex->session_id_len == 0", __func__);
1944         /*
1945          * Expect a signature for each of the ctx->nnew private keys we
1946          * haven't seen before. They will be in the same order as the
1947          * ctx->keys where the corresponding ctx->keys_seen[i] == 0.
1948          */
1949         for (ndone = i = 0; i < ctx->nkeys; i++) {
1950                 if (ctx->keys_seen[i])
1951                         continue;
1952                 /* Prepare data to be signed: session ID, unique string, key */
1953                 sshbuf_reset(signdata);
1954                 if ( (r = sshbuf_put_cstring(signdata,
1955                     "hostkeys-prove-00@openssh.com")) != 0 ||
1956                     (r = sshbuf_put_string(signdata, ssh->kex->session_id,
1957                     ssh->kex->session_id_len)) != 0 ||
1958                     (r = sshkey_puts(ctx->keys[i], signdata)) != 0)
1959                         fatal("%s: failed to prepare signature: %s",
1960                             __func__, ssh_err(r));
1961                 /* Extract and verify signature */
1962                 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) {
1963                         error("%s: couldn't parse message: %s",
1964                             __func__, ssh_err(r));
1965                         goto out;
1966                 }
1967                 /*
1968                  * For RSA keys, prefer to use the signature type negotiated
1969                  * during KEX to the default (SHA1).
1970                  */
1971                 use_kexsigtype = kexsigtype == KEY_RSA &&
1972                     sshkey_type_plain(ctx->keys[i]->type) == KEY_RSA;
1973                 if ((r = sshkey_verify(ctx->keys[i], sig, siglen,
1974                     sshbuf_ptr(signdata), sshbuf_len(signdata),
1975                     use_kexsigtype ? ssh->kex->hostkey_alg : NULL, 0)) != 0) {
1976                         error("%s: server gave bad signature for %s key %zu",
1977                             __func__, sshkey_type(ctx->keys[i]), i);
1978                         goto out;
1979                 }
1980                 /* Key is good. Mark it as 'seen' */
1981                 ctx->keys_seen[i] = 2;
1982                 ndone++;
1983         }
1984         if (ndone != ctx->nnew)
1985                 fatal("%s: ndone != ctx->nnew (%zu / %zu)", __func__,
1986                     ndone, ctx->nnew);  /* Shouldn't happen */
1987         ssh_packet_check_eom(ssh);
1988
1989         /* Make the edits to known_hosts */
1990         update_known_hosts(ctx);
1991  out:
1992         hostkeys_update_ctx_free(ctx);
1993 }
1994
1995 /*
1996  * Returns non-zero if the key is accepted by HostkeyAlgorithms.
1997  * Made slightly less trivial by the multiple RSA signature algorithm names.
1998  */
1999 static int
2000 key_accepted_by_hostkeyalgs(const struct sshkey *key)
2001 {
2002         const char *ktype = sshkey_ssh_name(key);
2003         const char *hostkeyalgs = options.hostkeyalgorithms != NULL ?
2004             options.hostkeyalgorithms : KEX_DEFAULT_PK_ALG;
2005
2006         if (key == NULL || key->type == KEY_UNSPEC)
2007                 return 0;
2008         if (key->type == KEY_RSA &&
2009             (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 ||
2010             match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1))
2011                 return 1;
2012         return match_pattern_list(ktype, hostkeyalgs, 0) == 1;
2013 }
2014
2015 /*
2016  * Handle hostkeys-00@openssh.com global request to inform the client of all
2017  * the server's hostkeys. The keys are checked against the user's
2018  * HostkeyAlgorithms preference before they are accepted.
2019  */
2020 static int
2021 client_input_hostkeys(void)
2022 {
2023         struct ssh *ssh = active_state; /* XXX */
2024         const u_char *blob = NULL;
2025         size_t i, len = 0;
2026         struct sshbuf *buf = NULL;
2027         struct sshkey *key = NULL, **tmp;
2028         int r;
2029         char *fp;
2030         static int hostkeys_seen = 0; /* XXX use struct ssh */
2031         extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */
2032         struct hostkeys_update_ctx *ctx = NULL;
2033
2034         if (hostkeys_seen)
2035                 fatal("%s: server already sent hostkeys", __func__);
2036         if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK &&
2037             options.batch_mode)
2038                 return 1; /* won't ask in batchmode, so don't even try */
2039         if (!options.update_hostkeys || options.num_user_hostfiles <= 0)
2040                 return 1;
2041
2042         ctx = xcalloc(1, sizeof(*ctx));
2043         while (ssh_packet_remaining(ssh) > 0) {
2044                 sshkey_free(key);
2045                 key = NULL;
2046                 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) {
2047                         error("%s: couldn't parse message: %s",
2048                             __func__, ssh_err(r));
2049                         goto out;
2050                 }
2051                 if ((r = sshkey_from_blob(blob, len, &key)) != 0) {
2052                         error("%s: parse key: %s", __func__, ssh_err(r));
2053                         goto out;
2054                 }
2055                 fp = sshkey_fingerprint(key, options.fingerprint_hash,
2056                     SSH_FP_DEFAULT);
2057                 debug3("%s: received %s key %s", __func__,
2058                     sshkey_type(key), fp);
2059                 free(fp);
2060
2061                 if (!key_accepted_by_hostkeyalgs(key)) {
2062                         debug3("%s: %s key not permitted by HostkeyAlgorithms",
2063                             __func__, sshkey_ssh_name(key));
2064                         continue;
2065                 }
2066                 /* Skip certs */
2067                 if (sshkey_is_cert(key)) {
2068                         debug3("%s: %s key is a certificate; skipping",
2069                             __func__, sshkey_ssh_name(key));
2070                         continue;
2071                 }
2072                 /* Ensure keys are unique */
2073                 for (i = 0; i < ctx->nkeys; i++) {
2074                         if (sshkey_equal(key, ctx->keys[i])) {
2075                                 error("%s: received duplicated %s host key",
2076                                     __func__, sshkey_ssh_name(key));
2077                                 goto out;
2078                         }
2079                 }
2080                 /* Key is good, record it */
2081                 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1,
2082                     sizeof(*ctx->keys))) == NULL)
2083                         fatal("%s: recallocarray failed nkeys = %zu",
2084                             __func__, ctx->nkeys);
2085                 ctx->keys = tmp;
2086                 ctx->keys[ctx->nkeys++] = key;
2087                 key = NULL;
2088         }
2089
2090         if (ctx->nkeys == 0) {
2091                 debug("%s: server sent no hostkeys", __func__);
2092                 goto out;
2093         }
2094
2095         if ((ctx->keys_seen = calloc(ctx->nkeys,
2096             sizeof(*ctx->keys_seen))) == NULL)
2097                 fatal("%s: calloc failed", __func__);
2098
2099         get_hostfile_hostname_ipaddr(host,
2100             options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL,
2101             options.port, &ctx->host_str,
2102             options.check_host_ip ? &ctx->ip_str : NULL);
2103
2104         /* Find which keys we already know about. */
2105         if ((r = hostkeys_foreach(options.user_hostfiles[0], hostkeys_find,
2106             ctx, ctx->host_str, ctx->ip_str,
2107             HKF_WANT_PARSE_KEY|HKF_WANT_MATCH)) != 0) {
2108                 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r));
2109                 goto out;
2110         }
2111
2112         /* Figure out if we have any new keys to add */
2113         ctx->nnew = 0;
2114         for (i = 0; i < ctx->nkeys; i++) {
2115                 if (!ctx->keys_seen[i])
2116                         ctx->nnew++;
2117         }
2118
2119         debug3("%s: %zu keys from server: %zu new, %zu retained. %zu to remove",
2120             __func__, ctx->nkeys, ctx->nnew, ctx->nkeys - ctx->nnew, ctx->nold);
2121
2122         if (ctx->nnew == 0 && ctx->nold != 0) {
2123                 /* We have some keys to remove. Just do it. */
2124                 update_known_hosts(ctx);
2125         } else if (ctx->nnew != 0) {
2126                 /*
2127                  * We have received hitherto-unseen keys from the server.
2128                  * Ask the server to confirm ownership of the private halves.
2129                  */
2130                 debug3("%s: asking server to prove ownership for %zu keys",
2131                     __func__, ctx->nnew);
2132                 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
2133                     (r = sshpkt_put_cstring(ssh,
2134                     "hostkeys-prove-00@openssh.com")) != 0 ||
2135                     (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */
2136                         fatal("%s: cannot prepare packet: %s",
2137                             __func__, ssh_err(r));
2138                 if ((buf = sshbuf_new()) == NULL)
2139                         fatal("%s: sshbuf_new", __func__);
2140                 for (i = 0; i < ctx->nkeys; i++) {
2141                         if (ctx->keys_seen[i])
2142                                 continue;
2143                         sshbuf_reset(buf);
2144                         if ((r = sshkey_putb(ctx->keys[i], buf)) != 0)
2145                                 fatal("%s: sshkey_putb: %s",
2146                                     __func__, ssh_err(r));
2147                         if ((r = sshpkt_put_stringb(ssh, buf)) != 0)
2148                                 fatal("%s: sshpkt_put_string: %s",
2149                                     __func__, ssh_err(r));
2150                 }
2151                 if ((r = sshpkt_send(ssh)) != 0)
2152                         fatal("%s: sshpkt_send: %s", __func__, ssh_err(r));
2153                 client_register_global_confirm(
2154                     client_global_hostkeys_private_confirm, ctx);
2155                 ctx = NULL;  /* will be freed in callback */
2156         }
2157
2158         /* Success */
2159  out:
2160         hostkeys_update_ctx_free(ctx);
2161         sshkey_free(key);
2162         sshbuf_free(buf);
2163         /*
2164          * NB. Return success for all cases. The server doesn't need to know
2165          * what the client does with its hosts file.
2166          */
2167         return 1;
2168 }
2169
2170 static int
2171 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh)
2172 {
2173         char *rtype;
2174         int want_reply;
2175         int success = 0;
2176
2177         rtype = packet_get_cstring(NULL);
2178         want_reply = packet_get_char();
2179         debug("client_input_global_request: rtype %s want_reply %d",
2180             rtype, want_reply);
2181         if (strcmp(rtype, "hostkeys-00@openssh.com") == 0)
2182                 success = client_input_hostkeys();
2183         if (want_reply) {
2184                 packet_start(success ?
2185                     SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
2186                 packet_send();
2187                 packet_write_wait();
2188         }
2189         free(rtype);
2190         return 0;
2191 }
2192
2193 void
2194 client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem,
2195     const char *term, struct termios *tiop, int in_fd, struct sshbuf *cmd,
2196     char **env)
2197 {
2198         int i, j, matched, len;
2199         char *name, *val;
2200         Channel *c = NULL;
2201
2202         debug2("%s: id %d", __func__, id);
2203
2204         if ((c = channel_lookup(ssh, id)) == NULL)
2205                 fatal("%s: channel %d: unknown channel", __func__, id);
2206
2207         packet_set_interactive(want_tty,
2208             options.ip_qos_interactive, options.ip_qos_bulk);
2209
2210         if (want_tty) {
2211                 struct winsize ws;
2212
2213                 /* Store window size in the packet. */
2214                 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0)
2215                         memset(&ws, 0, sizeof(ws));
2216
2217                 channel_request_start(ssh, id, "pty-req", 1);
2218                 client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY);
2219                 packet_put_cstring(term != NULL ? term : "");
2220                 packet_put_int((u_int)ws.ws_col);
2221                 packet_put_int((u_int)ws.ws_row);
2222                 packet_put_int((u_int)ws.ws_xpixel);
2223                 packet_put_int((u_int)ws.ws_ypixel);
2224                 if (tiop == NULL)
2225                         tiop = get_saved_tio();
2226                 ssh_tty_make_modes(ssh, -1, tiop);
2227                 packet_send();
2228                 /* XXX wait for reply */
2229                 c->client_tty = 1;
2230         }
2231
2232         /* Transfer any environment variables from client to server */
2233         if (options.num_send_env != 0 && env != NULL) {
2234                 debug("Sending environment.");
2235                 for (i = 0; env[i] != NULL; i++) {
2236                         /* Split */
2237                         name = xstrdup(env[i]);
2238                         if ((val = strchr(name, '=')) == NULL) {
2239                                 free(name);
2240                                 continue;
2241                         }
2242                         *val++ = '\0';
2243
2244                         matched = 0;
2245                         for (j = 0; j < options.num_send_env; j++) {
2246                                 if (match_pattern(name, options.send_env[j])) {
2247                                         matched = 1;
2248                                         break;
2249                                 }
2250                         }
2251                         if (!matched) {
2252                                 debug3("Ignored env %s", name);
2253                                 free(name);
2254                                 continue;
2255                         }
2256
2257                         debug("Sending env %s = %s", name, val);
2258                         channel_request_start(ssh, id, "env", 0);
2259                         packet_put_cstring(name);
2260                         packet_put_cstring(val);
2261                         packet_send();
2262                         free(name);
2263                 }
2264         }
2265         for (i = 0; i < options.num_setenv; i++) {
2266                 /* Split */
2267                 name = xstrdup(options.setenv[i]);
2268                 if ((val = strchr(name, '=')) == NULL) {
2269                         free(name);
2270                         continue;
2271                 }
2272                 *val++ = '\0';
2273
2274                 debug("Setting env %s = %s", name, val);
2275                 channel_request_start(ssh, id, "env", 0);
2276                 packet_put_cstring(name);
2277                 packet_put_cstring(val);
2278                 packet_send();
2279                 free(name);
2280         }
2281
2282         len = sshbuf_len(cmd);
2283         if (len > 0) {
2284                 if (len > 900)
2285                         len = 900;
2286                 if (want_subsystem) {
2287                         debug("Sending subsystem: %.*s",
2288                             len, (const u_char*)sshbuf_ptr(cmd));
2289                         channel_request_start(ssh, id, "subsystem", 1);
2290                         client_expect_confirm(ssh, id, "subsystem",
2291                             CONFIRM_CLOSE);
2292                 } else {
2293                         debug("Sending command: %.*s",
2294                             len, (const u_char*)sshbuf_ptr(cmd));
2295                         channel_request_start(ssh, id, "exec", 1);
2296                         client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE);
2297                 }
2298                 packet_put_string(sshbuf_ptr(cmd), sshbuf_len(cmd));
2299                 packet_send();
2300         } else {
2301                 channel_request_start(ssh, id, "shell", 1);
2302                 client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE);
2303                 packet_send();
2304         }
2305 }
2306
2307 static void
2308 client_init_dispatch(void)
2309 {
2310         dispatch_init(&dispatch_protocol_error);
2311
2312         dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
2313         dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
2314         dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
2315         dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
2316         dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
2317         dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
2318         dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
2319         dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
2320         dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
2321         dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm);
2322         dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm);
2323         dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);
2324
2325         /* rekeying */
2326         dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
2327
2328         /* global request reply messages */
2329         dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
2330         dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
2331 }
2332
2333 void
2334 client_stop_mux(void)
2335 {
2336         if (options.control_path != NULL && muxserver_sock != -1)
2337                 unlink(options.control_path);
2338         /*
2339          * If we are in persist mode, or don't have a shell, signal that we
2340          * should close when all active channels are closed.
2341          */
2342         if (options.control_persist || no_shell_flag) {
2343                 session_closed = 1;
2344                 setproctitle("[stopped mux]");
2345         }
2346 }
2347
2348 /* client specific fatal cleanup */
2349 void
2350 cleanup_exit(int i)
2351 {
2352         leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
2353         leave_non_blocking();
2354         if (options.control_path != NULL && muxserver_sock != -1)
2355                 unlink(options.control_path);
2356         ssh_kill_proxy_command();
2357         _exit(i);
2358 }