openssh/ssh.c

   1 /* $OpenBSD: ssh.c,v 1.294 2006/10/06 02:29:19 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  * Ssh client program.  This program can be used to log into a remote machine.
   7  * The software supports strong authentication, encryption, and forwarding
   8  * of X11, TCP/IP, and authentication connections.
   9  *
  10  * As far as I am concerned, the code I have written for this software
  11  * can be used freely for any purpose.  Any derived versions of this
  12  * software must be clearly marked as such, and if the derived work is
  13  * incompatible with the protocol description in the RFC file, it must be
  14  * called by a name other than "ssh" or "Secure Shell".
  15  *
  16  * Copyright (c) 1999 Niels Provos.  All rights reserved.
  17  * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl.  All rights reserved.
  18  *
  19  * Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
  20  * in Canada (German citizen).
  21  *
  22  * Redistribution and use in source and binary forms, with or without
  23  * modification, are permitted provided that the following conditions
  24  * are met:
  25  * 1. Redistributions of source code must retain the above copyright
  26  *    notice, this list of conditions and the following disclaimer.
  27  * 2. Redistributions in binary form must reproduce the above copyright
  28  *    notice, this list of conditions and the following disclaimer in the
  29  *    documentation and/or other materials provided with the distribution.
  30  *
  31  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  32  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  33  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  34  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  35  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  36  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  37  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  38  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  39  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  40  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  41  */
  42
  43 #include "includes.h"
  44
  45 #include <sys/types.h>
  46 #ifdef HAVE_SYS_STAT_H
  47 # include <sys/stat.h>
  48 #endif
  49 #include <sys/resource.h>
  50 #include <sys/ioctl.h>
  51 #include <sys/socket.h>
  52 #include <sys/un.h>
  53
  54 #include <ctype.h>
  55 #include <errno.h>
  56 #include <fcntl.h>
  57 #include <netdb.h>
  58 #ifdef HAVE_PATHS_H
  59 #include <paths.h>
  60 #endif
  61 #include <pwd.h>
  62 #include <signal.h>
  63 #include <stdarg.h>
  64 #include <stddef.h>
  65 #include <stdio.h>
  66 #include <stdlib.h>
  67 #include <string.h>
  68 #include <unistd.h>
  69
  70 #include <netinet/in.h>
  71 #include <arpa/inet.h>
  72
  73 #include <openssl/evp.h>
  74 #include <openssl/err.h>
  75
  76 #include "xmalloc.h"
  77 #include "ssh.h"
  78 #include "ssh1.h"
  79 #include "ssh2.h"
  80 #include "compat.h"
  81 #include "cipher.h"
  82 #include "packet.h"
  83 #include "buffer.h"
  84 #include "channels.h"
  85 #include "key.h"
  86 #include "authfd.h"
  87 #include "authfile.h"
  88 #include "pathnames.h"
  89 #include "dispatch.h"
  90 #include "clientloop.h"
  91 #include "log.h"
  92 #include "readconf.h"
  93 #include "sshconnect.h"
  94 #include "misc.h"
  95 #include "kex.h"
  96 #include "mac.h"
  97 #include "sshpty.h"
  98 #include "match.h"
  99 #include "msg.h"
 100 #include "monitor_fdpass.h"
 101 #include "uidswap.h"
 102 #include "version.h"
 103
 104 #ifdef SMARTCARD
 105 #include "scard.h"
 106 #endif
 107
 108 extern char *__progname;
 109
 110 /* Flag indicating whether debug mode is on.  This can be set on the command line. */
 111 int debug_flag = 0;
 112
 113 /* Flag indicating whether a tty should be allocated */
 114 int tty_flag = 0;
 115 int no_tty_flag = 0;
 116 int force_tty_flag = 0;
 117
 118 /* don't exec a shell */
 119 int no_shell_flag = 0;
 120
 121 /*
 122  * Flag indicating that nothing should be read from stdin.  This can be set
 123  * on the command line.
 124  */
 125 int stdin_null_flag = 0;
 126
 127 /*
 128  * Flag indicating that ssh should fork after authentication.  This is useful
 129  * so that the passphrase can be entered manually, and then ssh goes to the
 130  * background.
 131  */
 132 int fork_after_authentication_flag = 0;
 133
 134 /*
 135  * General data structure for command line options and options configurable
 136  * in configuration files.  See readconf.h.
 137  */
 138 Options options;
 139
 140 /* optional user configfile */
 141 char *config = NULL;
 142
 143 /*
 144  * Name of the host we are connecting to.  This is the name given on the
 145  * command line, or the HostName specified for the user-supplied name in a
 146  * configuration file.
 147  */
 148 char *host;
 149
 150 /* socket address the host resolves to */
 151 struct sockaddr_storage hostaddr;
 152
 153 /* Private host keys. */
 154 Sensitive sensitive_data;
 155
 156 /* Original real UID. */
 157 uid_t original_real_uid;
 158 uid_t original_effective_uid;
 159
 160 /* command to be executed */
 161 Buffer command;
 162
 163 /* Should we execute a command or invoke a subsystem? */
 164 int subsystem_flag = 0;
 165
 166 /* # of replies received for global requests */
 167 static int client_global_request_id = 0;
 168
 169 /* pid of proxycommand child process */
 170 pid_t proxy_command_pid = 0;
 171
 172 /* fd to control socket */
 173 int control_fd = -1;
 174
 175 /* Multiplexing control command */
 176 static u_int mux_command = 0;
 177
 178 /* Only used in control client mode */
 179 volatile sig_atomic_t control_client_terminate = 0;
 180 u_int control_server_pid = 0;
 181
 182 /* Prints a help message to the user.  This function never returns. */
 183
 184 static void
 185 usage(void)
 186 {
 187         fprintf(stderr,
 188 "usage: ssh [-1246AaCfgkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]\n"
 189 "           [-D [bind_address:]port] [-e escape_char] [-F configfile]\n"
 190 "           [-i identity_file] [-L [bind_address:]port:host:hostport]\n"
 191 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
 192 "           [-R [bind_address:]port:host:hostport] [-S ctl_path]\n"
 193 "           [-w local_tun[:remote_tun]] [user@]hostname [command]\n"
 194         );
 195         exit(255);
 196 }
 197
 198 static int ssh_session(void);
 199 static int ssh_session2(void);
 200 static void load_public_identity_files(void);
 201 static void control_client(const char *path);
 202
 203 /*
 204  * Main program for the ssh client.
 205  */
 206 int
 207 main(int ac, char **av)
 208 {
 209         int i, opt, exit_status;
 210         char *p, *cp, *line, buf[256];
 211         struct stat st;
 212         struct passwd *pw;
 213         int dummy;
 214         extern int optind, optreset;
 215         extern char *optarg;
 216         struct servent *sp;
 217         Forward fwd;
 218
 219         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 220         sanitise_stdfd();
 221
 222         __progname = ssh_get_progname(av[0]);
 223         init_rng();
 224
 225         /*
 226          * Save the original real uid.  It will be needed later (uid-swapping
 227          * may clobber the real uid).
 228          */
 229         original_real_uid = getuid();
 230         original_effective_uid = geteuid();
 231
 232         /*
 233          * Use uid-swapping to give up root privileges for the duration of
 234          * option processing.  We will re-instantiate the rights when we are
 235          * ready to create the privileged port, and will permanently drop
 236          * them when the port has been created (actually, when the connection
 237          * has been made, as we may need to create the port several times).
 238          */
 239         PRIV_END;
 240
 241 #ifdef HAVE_SETRLIMIT
 242         /* If we are installed setuid root be careful to not drop core. */
 243         if (original_real_uid != original_effective_uid) {
 244                 struct rlimit rlim;
 245                 rlim.rlim_cur = rlim.rlim_max = 0;
 246                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 247                         fatal("setrlimit failed: %.100s", strerror(errno));
 248         }
 249 #endif
 250         /* Get user data. */
 251         pw = getpwuid(original_real_uid);
 252         if (!pw) {
 253                 logit("You don't exist, go away!");
 254                 exit(255);
 255         }
 256         /* Take a copy of the returned structure. */
 257         pw = pwcopy(pw);
 258
 259         /*
 260          * Set our umask to something reasonable, as some files are created
 261          * with the default umask.  This will make them world-readable but
 262          * writable only by the owner, which is ok for all files for which we
 263          * don't set the modes explicitly.
 264          */
 265         umask(022);
 266
 267         /* Initialize option structure to indicate that no values have been set. */
 268         initialize_options(&options);
 269
 270         /* Parse command-line arguments. */
 271         host = NULL;
 272
 273  again:
 274         while ((opt = getopt(ac, av,
 275             "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:MNO:PR:S:TVw:XY")) != -1) {
 276                 switch (opt) {
 277                 case '1':
 278                         options.protocol = SSH_PROTO_1;
 279                         break;
 280                 case '2':
 281                         options.protocol = SSH_PROTO_2;
 282                         break;
 283                 case '4':
 284                         options.address_family = AF_INET;
 285                         break;
 286                 case '6':
 287                         options.address_family = AF_INET6;
 288                         break;
 289                 case 'n':
 290                         stdin_null_flag = 1;
 291                         break;
 292                 case 'f':
 293                         fork_after_authentication_flag = 1;
 294                         stdin_null_flag = 1;
 295                         break;
 296                 case 'x':
 297                         options.forward_x11 = 0;
 298                         break;
 299                 case 'X':
 300                         options.forward_x11 = 1;
 301                         break;
 302                 case 'Y':
 303                         options.forward_x11 = 1;
 304                         options.forward_x11_trusted = 1;
 305                         break;
 306                 case 'g':
 307                         options.gateway_ports = 1;
 308                         break;
 309                 case 'O':
 310                         if (strcmp(optarg, "check") == 0)
 311                                 mux_command = SSHMUX_COMMAND_ALIVE_CHECK;
 312                         else if (strcmp(optarg, "exit") == 0)
 313                                 mux_command = SSHMUX_COMMAND_TERMINATE;
 314                         else
 315                                 fatal("Invalid multiplex command.");
 316                         break;
 317                 case 'P':       /* deprecated */
 318                         options.use_privileged_port = 0;
 319                         break;
 320                 case 'a':
 321                         options.forward_agent = 0;
 322                         break;
 323                 case 'A':
 324                         options.forward_agent = 1;
 325                         break;
 326                 case 'k':
 327                         options.gss_deleg_creds = 0;
 328                         break;
 329                 case 'i':
 330                         if (stat(optarg, &st) < 0) {
 331                                 fprintf(stderr, "Warning: Identity file %s "
 332                                     "not accessible: %s.\n", optarg,
 333                                     strerror(errno));
 334                                 break;
 335                         }
 336                         if (options.num_identity_files >=
 337                             SSH_MAX_IDENTITY_FILES)
 338                                 fatal("Too many identity files specified "
 339                                     "(max %d)", SSH_MAX_IDENTITY_FILES);
 340                         options.identity_files[options.num_identity_files++] =
 341                             xstrdup(optarg);
 342                         break;
 343                 case 'I':
 344 #ifdef SMARTCARD
 345                         options.smartcard_device = xstrdup(optarg);
 346 #else
 347                         fprintf(stderr, "no support for smartcards.\n");
 348 #endif
 349                         break;
 350                 case 't':
 351                         if (tty_flag)
 352                                 force_tty_flag = 1;
 353                         tty_flag = 1;
 354                         break;
 355                 case 'v':
 356                         if (debug_flag == 0) {
 357                                 debug_flag = 1;
 358                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 359                         } else {
 360                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
 361                                         options.log_level++;
 362                                 break;
 363                         }
 364                         /* FALLTHROUGH */
 365                 case 'V':
 366                         fprintf(stderr, "%s, %s\n",
 367                             SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
 368                         if (opt == 'V')
 369                                 exit(0);
 370                         break;
 371                 case 'w':
 372                         if (options.tun_open == -1)
 373                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 374                         options.tun_local = a2tun(optarg, &options.tun_remote);
 375                         if (options.tun_local == SSH_TUNID_ERR) {
 376                                 fprintf(stderr, "Bad tun device '%s'\n", optarg);
 377                                 exit(255);
 378                         }
 379                         break;
 380                 case 'q':
 381                         options.log_level = SYSLOG_LEVEL_QUIET;
 382                         break;
 383                 case 'e':
 384                         if (optarg[0] == '^' && optarg[2] == 0 &&
 385                             (u_char) optarg[1] >= 64 &&
 386                             (u_char) optarg[1] < 128)
 387                                 options.escape_char = (u_char) optarg[1] & 31;
 388                         else if (strlen(optarg) == 1)
 389                                 options.escape_char = (u_char) optarg[0];
 390                         else if (strcmp(optarg, "none") == 0)
 391                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 392                         else {
 393                                 fprintf(stderr, "Bad escape character '%s'.\n",
 394                                     optarg);
 395                                 exit(255);
 396                         }
 397                         break;
 398                 case 'c':
 399                         if (ciphers_valid(optarg)) {
 400                                 /* SSH2 only */
 401                                 options.ciphers = xstrdup(optarg);
 402                                 options.cipher = SSH_CIPHER_INVALID;
 403                         } else {
 404                                 /* SSH1 only */
 405                                 options.cipher = cipher_number(optarg);
 406                                 if (options.cipher == -1) {
 407                                         fprintf(stderr,
 408                                             "Unknown cipher type '%s'\n",
 409                                             optarg);
 410                                         exit(255);
 411                                 }
 412                                 if (options.cipher == SSH_CIPHER_3DES)
 413                                         options.ciphers = "3des-cbc";
 414                                 else if (options.cipher == SSH_CIPHER_BLOWFISH)
 415                                         options.ciphers = "blowfish-cbc";
 416                                 else
 417                                         options.ciphers = (char *)-1;
 418                         }
 419                         break;
 420                 case 'm':
 421                         if (mac_valid(optarg))
 422                                 options.macs = xstrdup(optarg);
 423                         else {
 424                                 fprintf(stderr, "Unknown mac type '%s'\n",
 425                                     optarg);
 426                                 exit(255);
 427                         }
 428                         break;
 429                 case 'M':
 430                         if (options.control_master == SSHCTL_MASTER_YES)
 431                                 options.control_master = SSHCTL_MASTER_ASK;
 432                         else
 433                                 options.control_master = SSHCTL_MASTER_YES;
 434                         break;
 435                 case 'p':
 436                         options.port = a2port(optarg);
 437                         if (options.port == 0) {
 438                                 fprintf(stderr, "Bad port '%s'\n", optarg);
 439                                 exit(255);
 440                         }
 441                         break;
 442                 case 'l':
 443                         options.user = optarg;
 444                         break;
 445
 446                 case 'L':
 447                         if (parse_forward(&fwd, optarg))
 448                                 add_local_forward(&options, &fwd);
 449                         else {
 450                                 fprintf(stderr,
 451                                     "Bad local forwarding specification '%s'\n",
 452                                     optarg);
 453                                 exit(255);
 454                         }
 455                         break;
 456
 457                 case 'R':
 458                         if (parse_forward(&fwd, optarg)) {
 459                                 add_remote_forward(&options, &fwd);
 460                         } else {
 461                                 fprintf(stderr,
 462                                     "Bad remote forwarding specification "
 463                                     "'%s'\n", optarg);
 464                                 exit(255);
 465                         }
 466                         break;
 467
 468                 case 'D':
 469                         cp = p = xstrdup(optarg);
 470                         memset(&fwd, '\0', sizeof(fwd));
 471                         fwd.connect_host = "socks";
 472                         if ((fwd.listen_host = hpdelim(&cp)) == NULL) {
 473                                 fprintf(stderr, "Bad dynamic forwarding "
 474                                     "specification '%.100s'\n", optarg);
 475                                 exit(255);
 476                         }
 477                         if (cp != NULL) {
 478                                 fwd.listen_port = a2port(cp);
 479                                 fwd.listen_host = cleanhostname(fwd.listen_host);
 480                         } else {
 481                                 fwd.listen_port = a2port(fwd.listen_host);
 482                                 fwd.listen_host = NULL;
 483                         }
 484
 485                         if (fwd.listen_port == 0) {
 486                                 fprintf(stderr, "Bad dynamic port '%s'\n",
 487                                     optarg);
 488                                 exit(255);
 489                         }
 490                         add_local_forward(&options, &fwd);
 491                         xfree(p);
 492                         break;
 493
 494                 case 'C':
 495                         options.compression = 1;
 496                         break;
 497                 case 'N':
 498                         no_shell_flag = 1;
 499                         no_tty_flag = 1;
 500                         break;
 501                 case 'o':
 502                         dummy = 1;
 503                         line = xstrdup(optarg);
 504                         if (process_config_line(&options, host ? host : "",
 505                             line, "command-line", 0, &dummy) != 0)
 506                                 exit(255);
 507                         xfree(line);
 508                         break;
 509                 case 'T':
 510                         no_tty_flag = 1;
 511                         /* ensure that the user doesn't try to backdoor a */
 512                         /* null cipher switch on an interactive session */
 513                         /* so explicitly disable it no matter what */
 514                         options.none_switch=0;
 515                         break;
 516                 case 's':
 517                         subsystem_flag = 1;
 518                         break;
 519                 case 'S':
 520                         if (options.control_path != NULL)
 521                                 free(options.control_path);
 522                         options.control_path = xstrdup(optarg);
 523                         break;
 524                 case 'b':
 525                         options.bind_address = optarg;
 526                         break;
 527                 case 'F':
 528                         config = optarg;
 529                         break;
 530                 default:
 531                         usage();
 532                 }
 533         }
 534
 535         ac -= optind;
 536         av += optind;
 537
 538         if (ac > 0 && !host && **av != '-') {
 539                 if (strrchr(*av, '@')) {
 540                         p = xstrdup(*av);
 541                         cp = strrchr(p, '@');
 542                         if (cp == NULL || cp == p)
 543                                 usage();
 544                         options.user = p;
 545                         *cp = '\0';
 546                         host = ++cp;
 547                 } else
 548                         host = *av;
 549                 if (ac > 1) {
 550                         optind = optreset = 1;
 551                         goto again;
 552                 }
 553                 ac--, av++;
 554         }
 555
 556         /* Check that we got a host name. */
 557         if (!host)
 558                 usage();
 559
 560         SSLeay_add_all_algorithms();
 561         ERR_load_crypto_strings();
 562
 563         /* Initialize the command to execute on remote host. */
 564         buffer_init(&command);
 565
 566         /*
 567          * Save the command to execute on the remote host in a buffer. There
 568          * is no limit on the length of the command, except by the maximum
 569          * packet size.  Also sets the tty flag if there is no command.
 570          */
 571         if (!ac) {
 572                 /* No command specified - execute shell on a tty. */
 573                 tty_flag = 1;
 574                 if (subsystem_flag) {
 575                         fprintf(stderr,
 576                             "You must specify a subsystem to invoke.\n");
 577                         usage();
 578                 }
 579         } else {
 580                 /* A command has been specified.  Store it into the buffer. */
 581                 for (i = 0; i < ac; i++) {
 582                         if (i)
 583                                 buffer_append(&command, " ", 1);
 584                         buffer_append(&command, av[i], strlen(av[i]));
 585                 }
 586         }
 587
 588         /* Cannot fork to background if no command. */
 589         if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag)
 590                 fatal("Cannot fork into background without a command to execute.");
 591
 592         /* Allocate a tty by default if no command specified. */
 593         if (buffer_len(&command) == 0)
 594                 tty_flag = 1;
 595
 596         /* Force no tty */
 597         if (no_tty_flag)
 598                 tty_flag = 0;
 599         /* Do not allocate a tty if stdin is not a tty. */
 600         if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) {
 601                 if (tty_flag)
 602                         logit("Pseudo-terminal will not be allocated because stdin is not a terminal.");
 603                 tty_flag = 0;
 604         }
 605
 606         /*
 607          * Initialize "log" output.  Since we are the client all output
 608          * actually goes to stderr.
 609          */
 610         log_init(av[0], options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
 611             SYSLOG_FACILITY_USER, 1);
 612
 613         /*
 614          * Read per-user configuration file.  Ignore the system wide config
 615          * file if the user specifies a config file on the command line.
 616          */
 617         if (config != NULL) {
 618                 if (!read_config_file(config, host, &options, 0))
 619                         fatal("Can't open user config file %.100s: "
 620                             "%.100s", config, strerror(errno));
 621         } else  {
 622             /*
 623              * Since the config file parsing code aborts if it sees
 624              * options it doesn't recognize, allow users to put
 625              * options specific to compile-time add-ons in alternate
 626              * config files so their primary config file will
 627              * interoperate SSH versions that don't support those
 628              * options.
 629              */
 630 #ifdef GSSAPI
 631                 snprintf(buf, sizeof buf, "%.100s/%.100s.gssapi", pw->pw_dir,
 632                     _PATH_SSH_USER_CONFFILE);
 633                 (void)read_config_file(buf, host, &options, 1);
 634 #ifdef GSI
 635                 snprintf(buf, sizeof buf, "%.100s/%.100s.gsi", pw->pw_dir,
 636                     _PATH_SSH_USER_CONFFILE);
 637                 (void)read_config_file(buf, host, &options, 1);
 638 #endif
 639 #if defined(KRB5)
 640                 snprintf(buf, sizeof buf, "%.100s/%.100s.krb", pw->pw_dir,
 641                     _PATH_SSH_USER_CONFFILE);
 642                 (void)read_config_file(buf, host, &options, 1);
 643 #endif
 644 #endif
 645                 snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir,
 646                     _PATH_SSH_USER_CONFFILE);
 647                 (void)read_config_file(buf, host, &options, 1);
 648
 649                 /* Read systemwide configuration file after use config. */
 650                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host,
 651                     &options, 0);
 652         }
 653
 654         /* Fill configuration defaults. */
 655         fill_default_options(&options);
 656
 657         channel_set_af(options.address_family);
 658
 659         /* reinit */
 660         log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1);
 661
 662         seed_rng();
 663
 664         if (options.user == NULL) {
 665                 options.user = xstrdup(pw->pw_name);
 666                 options.implicit = 1;
 667         }
 668         else options.implicit = 0;
 669
 670         if (options.hostname != NULL)
 671                 host = options.hostname;
 672
 673         /* force lowercase for hostkey matching */
 674         if (options.host_key_alias != NULL) {
 675                 for (p = options.host_key_alias; *p; p++)
 676                         if (isupper(*p))
 677                                 *p = (char)tolower(*p);
 678         }
 679
 680         /* Get default port if port has not been set. */
 681         if (options.port == 0) {
 682                 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
 683                 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT;
 684         }
 685
 686         if (options.proxy_command != NULL &&
 687             strcmp(options.proxy_command, "none") == 0)
 688                 options.proxy_command = NULL;
 689         if (options.control_path != NULL &&
 690             strcmp(options.control_path, "none") == 0)
 691                 options.control_path = NULL;
 692
 693         if (options.control_path != NULL) {
 694                 char thishost[NI_MAXHOST];
 695
 696                 if (gethostname(thishost, sizeof(thishost)) == -1)
 697                         fatal("gethostname: %s", strerror(errno));
 698                 snprintf(buf, sizeof(buf), "%d", options.port);
 699                 cp = tilde_expand_filename(options.control_path,
 700                     original_real_uid);
 701                 options.control_path = percent_expand(cp, "p", buf, "h", host,
 702                     "r", options.user, "l", thishost, (char *)NULL);
 703                 xfree(cp);
 704         }
 705         if (mux_command != 0 && options.control_path == NULL)
 706                 fatal("No ControlPath specified for \"-O\" command");
 707         if (options.control_path != NULL)
 708                 control_client(options.control_path);
 709
 710         /* Open a connection to the remote host. */
 711         if (ssh_connect(host, &hostaddr, options.port,
 712             options.address_family, options.connection_attempts,
 713 #ifdef HAVE_CYGWIN
 714             options.use_privileged_port,
 715 #else
 716             original_effective_uid == 0 && options.use_privileged_port,
 717 #endif
 718             options.proxy_command) != 0)
 719                 exit(255);
 720
 721         /*
 722          * If we successfully made the connection, load the host private key
 723          * in case we will need it later for combined rsa-rhosts
 724          * authentication. This must be done before releasing extra
 725          * privileges, because the file is only readable by root.
 726          * If we cannot access the private keys, load the public keys
 727          * instead and try to execute the ssh-keysign helper instead.
 728          */
 729         sensitive_data.nkeys = 0;
 730         sensitive_data.keys = NULL;
 731         sensitive_data.external_keysign = 0;
 732         if (options.rhosts_rsa_authentication ||
 733             options.hostbased_authentication) {
 734                 sensitive_data.nkeys = 3;
 735                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
 736                     sizeof(Key));
 737
 738                 PRIV_START;
 739                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
 740                     _PATH_HOST_KEY_FILE, "", NULL, NULL);
 741                 sensitive_data.keys[1] = key_load_private_type(KEY_DSA,
 742                     _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
 743                 sensitive_data.keys[2] = key_load_private_type(KEY_RSA,
 744                     _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
 745                 PRIV_END;
 746
 747                 if (options.hostbased_authentication == 1 &&
 748                     sensitive_data.keys[0] == NULL &&
 749                     sensitive_data.keys[1] == NULL &&
 750                     sensitive_data.keys[2] == NULL) {
 751                         sensitive_data.keys[1] = key_load_public(
 752                             _PATH_HOST_DSA_KEY_FILE, NULL);
 753                         sensitive_data.keys[2] = key_load_public(
 754                             _PATH_HOST_RSA_KEY_FILE, NULL);
 755                         sensitive_data.external_keysign = 1;
 756                 }
 757         }
 758         /*
 759          * Get rid of any extra privileges that we may have.  We will no
 760          * longer need them.  Also, extra privileges could make it very hard
 761          * to read identity files and other non-world-readable files from the
 762          * user's home directory if it happens to be on a NFS volume where
 763          * root is mapped to nobody.
 764          */
 765         if (original_effective_uid == 0) {
 766                 PRIV_START;
 767                 permanently_set_uid(pw);
 768         }
 769
 770         /*
 771          * Now that we are back to our own permissions, create ~/.ssh
 772          * directory if it doesn't already exist.
 773          */
 774         snprintf(buf, sizeof buf, "%.100s%s%.100s", pw->pw_dir, strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
 775         if (stat(buf, &st) < 0)
 776                 if (mkdir(buf, 0700) < 0)
 777                         error("Could not create directory '%.200s'.", buf);
 778
 779         /* load options.identity_files */
 780         load_public_identity_files();
 781
 782         /* Expand ~ in known host file names. */
 783         /* XXX mem-leaks: */
 784         options.system_hostfile =
 785             tilde_expand_filename(options.system_hostfile, original_real_uid);
 786         options.user_hostfile =
 787             tilde_expand_filename(options.user_hostfile, original_real_uid);
 788         options.system_hostfile2 =
 789             tilde_expand_filename(options.system_hostfile2, original_real_uid);
 790         options.user_hostfile2 =
 791             tilde_expand_filename(options.user_hostfile2, original_real_uid);
 792
 793         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
 794
 795         /* Log into the remote system.  This never returns if the login fails. */
 796         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, pw);
 797
 798         /* We no longer need the private host keys.  Clear them now. */
 799         if (sensitive_data.nkeys != 0) {
 800                 for (i = 0; i < sensitive_data.nkeys; i++) {
 801                         if (sensitive_data.keys[i] != NULL) {
 802                                 /* Destroys contents safely */
 803                                 debug3("clear hostkey %d", i);
 804                                 key_free(sensitive_data.keys[i]);
 805                                 sensitive_data.keys[i] = NULL;
 806                         }
 807                 }
 808                 xfree(sensitive_data.keys);
 809         }
 810         for (i = 0; i < options.num_identity_files; i++) {
 811                 if (options.identity_files[i]) {
 812                         xfree(options.identity_files[i]);
 813                         options.identity_files[i] = NULL;
 814                 }
 815                 if (options.identity_keys[i]) {
 816                         key_free(options.identity_keys[i]);
 817                         options.identity_keys[i] = NULL;
 818                 }
 819         }
 820
 821         exit_status = compat20 ? ssh_session2() : ssh_session();
 822         packet_close();
 823
 824         if (options.control_path != NULL && control_fd != -1)
 825                 unlink(options.control_path);
 826
 827         /*
 828          * Send SIGHUP to proxy command if used. We don't wait() in
 829          * case it hangs and instead rely on init to reap the child
 830          */
 831         if (proxy_command_pid > 1)
 832                 kill(proxy_command_pid, SIGHUP);
 833
 834         return exit_status;
 835 }
 836
 837 static void
 838 ssh_init_forwarding(void)
 839 {
 840         int success = 0;
 841         int i;
 842
 843         /* Initiate local TCP/IP port forwardings. */
 844         for (i = 0; i < options.num_local_forwards; i++) {
 845                 debug("Local connections to %.200s:%d forwarded to remote "
 846                     "address %.200s:%d",
 847                     (options.local_forwards[i].listen_host == NULL) ?
 848                     (options.gateway_ports ? "*" : "LOCALHOST") :
 849                     options.local_forwards[i].listen_host,
 850                     options.local_forwards[i].listen_port,
 851                     options.local_forwards[i].connect_host,
 852                     options.local_forwards[i].connect_port);
 853                 success += channel_setup_local_fwd_listener(
 854                     options.local_forwards[i].listen_host,
 855                     options.local_forwards[i].listen_port,
 856                     options.local_forwards[i].connect_host,
 857                     options.local_forwards[i].connect_port,
 858                     options.gateway_ports, options.hpn_disabled,
 859                     options.hpn_buffer_size);
 860         }
 861         if (i > 0 && success != i && options.exit_on_forward_failure)
 862                 fatal("Could not request local forwarding.");
 863         if (i > 0 && success == 0)
 864                 error("Could not request local forwarding.");
 865
 866         /* Initiate remote TCP/IP port forwardings. */
 867         for (i = 0; i < options.num_remote_forwards; i++) {
 868                 debug("Remote connections from %.200s:%d forwarded to "
 869                     "local address %.200s:%d",
 870                     (options.remote_forwards[i].listen_host == NULL) ?
 871                     "LOCALHOST" : options.remote_forwards[i].listen_host,
 872                     options.remote_forwards[i].listen_port,
 873                     options.remote_forwards[i].connect_host,
 874                     options.remote_forwards[i].connect_port);
 875                 if (channel_request_remote_forwarding(
 876                     options.remote_forwards[i].listen_host,
 877                     options.remote_forwards[i].listen_port,
 878                     options.remote_forwards[i].connect_host,
 879                     options.remote_forwards[i].connect_port) < 0) {
 880                         if (options.exit_on_forward_failure)
 881                                 fatal("Could not request remote forwarding.");
 882                         else
 883                                 logit("Warning: Could not request remote "
 884                                     "forwarding.");
 885                 }
 886         }
 887 }
 888
 889 static void
 890 check_agent_present(void)
 891 {
 892         if (options.forward_agent) {
 893                 /* Clear agent forwarding if we don't have an agent. */
 894                 if (!ssh_agent_present())
 895                         options.forward_agent = 0;
 896         }
 897 }
 898
 899 static int
 900 ssh_session(void)
 901 {
 902         int type;
 903         int interactive = 0;
 904         int have_tty = 0;
 905         struct winsize ws;
 906         char *cp;
 907         const char *display;
 908
 909         /* Enable compression if requested. */
 910         if (options.compression) {
 911                 debug("Requesting compression at level %d.", options.compression_level);
 912
 913                 if (options.compression_level < 1 || options.compression_level > 9)
 914                         fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
 915
 916                 /* Send the request. */
 917                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
 918                 packet_put_int(options.compression_level);
 919                 packet_send();
 920                 packet_write_wait();
 921                 type = packet_read();
 922                 if (type == SSH_SMSG_SUCCESS)
 923                         packet_start_compression(options.compression_level);
 924                 else if (type == SSH_SMSG_FAILURE)
 925                         logit("Warning: Remote host refused compression.");
 926                 else
 927                         packet_disconnect("Protocol error waiting for compression response.");
 928         }
 929         /* Allocate a pseudo tty if appropriate. */
 930         if (tty_flag) {
 931                 debug("Requesting pty.");
 932
 933                 /* Start the packet. */
 934                 packet_start(SSH_CMSG_REQUEST_PTY);
 935
 936                 /* Store TERM in the packet.  There is no limit on the
 937                    length of the string. */
 938                 cp = getenv("TERM");
 939                 if (!cp)
 940                         cp = "";
 941                 packet_put_cstring(cp);
 942
 943                 /* Store window size in the packet. */
 944                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
 945                         memset(&ws, 0, sizeof(ws));
 946                 packet_put_int((u_int)ws.ws_row);
 947                 packet_put_int((u_int)ws.ws_col);
 948                 packet_put_int((u_int)ws.ws_xpixel);
 949                 packet_put_int((u_int)ws.ws_ypixel);
 950
 951                 /* Store tty modes in the packet. */
 952                 tty_make_modes(fileno(stdin), NULL);
 953
 954                 /* Send the packet, and wait for it to leave. */
 955                 packet_send();
 956                 packet_write_wait();
 957
 958                 /* Read response from the server. */
 959                 type = packet_read();
 960                 if (type == SSH_SMSG_SUCCESS) {
 961                         interactive = 1;
 962                         have_tty = 1;
 963                 } else if (type == SSH_SMSG_FAILURE)
 964                         logit("Warning: Remote host failed or refused to allocate a pseudo tty.");
 965                 else
 966                         packet_disconnect("Protocol error waiting for pty request response.");
 967         }
 968         /* Request X11 forwarding if enabled and DISPLAY is set. */
 969         display = getenv("DISPLAY");
 970         if (options.forward_x11 && display != NULL) {
 971                 char *proto, *data;
 972                 /* Get reasonable local authentication information. */
 973                 client_x11_get_proto(display, options.xauth_location,
 974                     options.forward_x11_trusted, &proto, &data);
 975                 /* Request forwarding with authentication spoofing. */
 976                 debug("Requesting X11 forwarding with authentication spoofing.");
 977                 x11_request_forwarding_with_spoofing(0, display, proto, data);
 978
 979                 /* Read response from the server. */
 980                 type = packet_read();
 981                 if (type == SSH_SMSG_SUCCESS) {
 982                         interactive = 1;
 983                 } else if (type == SSH_SMSG_FAILURE) {
 984                         logit("Warning: Remote host denied X11 forwarding.");
 985                 } else {
 986                         packet_disconnect("Protocol error waiting for X11 forwarding");
 987                 }
 988         }
 989         /* Tell the packet module whether this is an interactive session. */
 990         packet_set_interactive(interactive);
 991
 992         /* Request authentication agent forwarding if appropriate. */
 993         check_agent_present();
 994
 995         if (options.forward_agent) {
 996                 debug("Requesting authentication agent forwarding.");
 997                 auth_request_forwarding();
 998
 999                 /* Read response from the server. */
1000                 type = packet_read();
1001                 packet_check_eom();
1002                 if (type != SSH_SMSG_SUCCESS)
1003                         logit("Warning: Remote host denied authentication agent forwarding.");
1004         }
1005
1006         /* Initiate port forwardings. */
1007         ssh_init_forwarding();
1008
1009         /* If requested, let ssh continue in the background. */
1010         if (fork_after_authentication_flag)
1011                 if (daemon(1, 1) < 0)
1012                         fatal("daemon() failed: %.200s", strerror(errno));
1013
1014         /*
1015          * If a command was specified on the command line, execute the
1016          * command now. Otherwise request the server to start a shell.
1017          */
1018         if (buffer_len(&command) > 0) {
1019                 int len = buffer_len(&command);
1020                 if (len > 900)
1021                         len = 900;
1022                 debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command));
1023                 packet_start(SSH_CMSG_EXEC_CMD);
1024                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1025                 packet_send();
1026                 packet_write_wait();
1027         } else {
1028                 debug("Requesting shell.");
1029                 packet_start(SSH_CMSG_EXEC_SHELL);
1030                 packet_send();
1031                 packet_write_wait();
1032         }
1033
1034         /* Enter the interactive session. */
1035         return client_loop(have_tty, tty_flag ?
1036             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1037 }
1038
1039 static void
1040 ssh_subsystem_reply(int type, u_int32_t seq, void *ctxt)
1041 {
1042         int id, len;
1043
1044         id = packet_get_int();
1045         len = buffer_len(&command);
1046         if (len > 900)
1047                 len = 900;
1048         packet_check_eom();
1049         if (type == SSH2_MSG_CHANNEL_FAILURE)
1050                 fatal("Request for subsystem '%.*s' failed on channel %d",
1051                     len, (u_char *)buffer_ptr(&command), id);
1052 }
1053
1054 void
1055 client_global_request_reply_fwd(int type, u_int32_t seq, void *ctxt)
1056 {
1057         int i;
1058
1059         i = client_global_request_id++;
1060         if (i >= options.num_remote_forwards)
1061                 return;
1062         debug("remote forward %s for: listen %d, connect %s:%d",
1063             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1064             options.remote_forwards[i].listen_port,
1065             options.remote_forwards[i].connect_host,
1066             options.remote_forwards[i].connect_port);
1067         if (type == SSH2_MSG_REQUEST_FAILURE) {
1068                 if (options.exit_on_forward_failure)
1069                         fatal("Error: remote port forwarding failed for "
1070                             "listen port %d",
1071                             options.remote_forwards[i].listen_port);
1072                 else
1073                         logit("Warning: remote port forwarding failed for "
1074                             "listen port %d",
1075                             options.remote_forwards[i].listen_port);
1076         }
1077 }
1078
1079 static void
1080 ssh_control_listener(void)
1081 {
1082         struct sockaddr_un addr;
1083         mode_t old_umask;
1084         int addr_len;
1085
1086         if (options.control_path == NULL ||
1087             options.control_master == SSHCTL_MASTER_NO)
1088                 return;
1089
1090         debug("setting up multiplex master socket");
1091
1092         memset(&addr, '\0', sizeof(addr));
1093         addr.sun_family = AF_UNIX;
1094         addr_len = offsetof(struct sockaddr_un, sun_path) +
1095             strlen(options.control_path) + 1;
1096
1097         if (strlcpy(addr.sun_path, options.control_path,
1098             sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
1099                 fatal("ControlPath too long");
1100
1101         if ((control_fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
1102                 fatal("%s socket(): %s", __func__, strerror(errno));
1103
1104         old_umask = umask(0177);
1105         if (bind(control_fd, (struct sockaddr *)&addr, addr_len) == -1) {
1106                 control_fd = -1;
1107                 if (errno == EINVAL || errno == EADDRINUSE)
1108                         fatal("ControlSocket %s already exists",
1109                             options.control_path);
1110                 else
1111                         fatal("%s bind(): %s", __func__, strerror(errno));
1112         }
1113         umask(old_umask);
1114
1115         if (listen(control_fd, 64) == -1)
1116                 fatal("%s listen(): %s", __func__, strerror(errno));
1117
1118         set_nonblock(control_fd);
1119 }
1120
1121 /* request pty/x11/agent/tcpfwd/shell for channel */
1122 static void
1123 ssh_session2_setup(int id, void *arg)
1124 {
1125         extern char **environ;
1126         const char *display;
1127         int interactive = tty_flag;
1128
1129         display = getenv("DISPLAY");
1130         if (options.forward_x11 && display != NULL) {
1131                 char *proto, *data;
1132                 /* Get reasonable local authentication information. */
1133                 client_x11_get_proto(display, options.xauth_location,
1134                     options.forward_x11_trusted, &proto, &data);
1135                 /* Request forwarding with authentication spoofing. */
1136                 debug("Requesting X11 forwarding with authentication spoofing.");
1137                 x11_request_forwarding_with_spoofing(id, display, proto, data);
1138                 interactive = 1;
1139                 /* XXX wait for reply */
1140         }
1141
1142         check_agent_present();
1143         if (options.forward_agent) {
1144                 debug("Requesting authentication agent forwarding.");
1145                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1146                 packet_send();
1147         }
1148
1149         if (options.tun_open != SSH_TUNMODE_NO) {
1150                 Channel *c;
1151                 int fd;
1152
1153                 debug("Requesting tun.");
1154                 if ((fd = tun_open(options.tun_local,
1155                     options.tun_open)) >= 0) {
1156                         if(options.hpn_disabled)
1157                                 c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1,
1158                                     CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1159                                     0, "tun", 1);
1160                         else
1161                                 c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1,
1162                                     options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT,
1163                                     0, "tun", 1);
1164                         c->datagram = 1;
1165 #if defined(SSH_TUN_FILTER)
1166                         if (options.tun_open == SSH_TUNMODE_POINTOPOINT)
1167                                 channel_register_filter(c->self, sys_tun_infilter,
1168                                     sys_tun_outfilter);
1169 #endif
1170                         packet_start(SSH2_MSG_CHANNEL_OPEN);
1171                         packet_put_cstring("tun@openssh.com");
1172                         packet_put_int(c->self);
1173                         packet_put_int(c->local_window_max);
1174                         packet_put_int(c->local_maxpacket);
1175                         packet_put_int(options.tun_open);
1176                         packet_put_int(options.tun_remote);
1177                         packet_send();
1178                 }
1179         }
1180
1181         client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1182             NULL, fileno(stdin), &command, environ, &ssh_subsystem_reply);
1183
1184         packet_set_interactive(interactive);
1185 }
1186
1187 /* open new channel for a session */
1188 static int
1189 ssh_session2_open(void)
1190 {
1191         Channel *c;
1192         int window, packetmax, in, out, err;
1193         int sock;
1194         int socksize;
1195         int socksizelen = sizeof(int);
1196
1197         if (stdin_null_flag) {
1198                 in = open(_PATH_DEVNULL, O_RDONLY);
1199         } else {
1200                 in = dup(STDIN_FILENO);
1201         }
1202         out = dup(STDOUT_FILENO);
1203         err = dup(STDERR_FILENO);
1204
1205         if (in < 0 || out < 0 || err < 0)
1206                 fatal("dup() in/out/err failed");
1207
1208         /* enable nonblocking unless tty */
1209         if (!isatty(in))
1210                 set_nonblock(in);
1211         if (!isatty(out))
1212                 set_nonblock(out);
1213         if (!isatty(err))
1214                 set_nonblock(err);
1215
1216         /* we need to check to see if what they want to do about buffer */
1217         /* sizes here. In a hpn to nonhpn connection we want to limit */
1218         /* the window size to something reasonable in case the far side */
1219         /* has the large window bug. In hpn to hpn connection we want to */
1220         /* use the max window size but allow the user to override it */
1221         /* lastly if they disabled hpn then use the ssh std window size */
1222
1223         /* so why don't we just do a getsockopt() here and set the */
1224         /* ssh window to that? In the case of a autotuning receive */
1225         /* window the window would get stuck at the initial buffer */
1226         /* size generally less than 96k. Therefore we need to set the */
1227         /* maximum ssh window size to the maximum hpn buffer size */
1228         /* unless the user hasspecifically set the hpnrcvbufpoll */
1229         /* to no. In which case we *can* just set the window to the */
1230         /* minimum of the hpn buffer size and tcp receive buffer size */
1231
1232         if(options.hpn_disabled)
1233         {
1234                 options.hpn_buffer_size = CHAN_SES_WINDOW_DEFAULT;
1235         }
1236         else if (datafellows & SSH_BUG_LARGEWINDOW)
1237         {
1238                 debug("HPN to Non-HPN Connection");
1239                 if (options.hpn_buffer_size < 0)
1240                         options.hpn_buffer_size = 2*1024*1024;
1241         }
1242         else
1243         {
1244                 if (options.hpn_buffer_size < 0)
1245                         options.hpn_buffer_size = BUFFER_MAX_LEN_HPN;
1246                 if (options.tcp_rcv_buf_poll <= 0)
1247                 {
1248                         /*create a socket but don't connect it */
1249                         /* we use that the get the rcv socket size */
1250                         sock = socket(AF_INET, SOCK_STREAM, 0);
1251                         /* if they are using the tcp_rcv_buf option */
1252                         /* attempt to set the buffer size to that */
1253                         if (options.tcp_rcv_buf)
1254                                 setsockopt(sock, SOL_SOCKET, SO_RCVBUF, (void *)&options.tcp_rcv_buf,
1255                                            sizeof(options.tcp_rcv_buf));
1256                         getsockopt(sock, SOL_SOCKET, SO_RCVBUF,
1257                                    &socksize, &socksizelen);
1258                         close(sock);
1259                         debug("socksize %d", socksize);
1260                         options.hpn_buffer_size = MIN(socksize,options.hpn_buffer_size);
1261                 }
1262                 else
1263                 {
1264                         if (options.tcp_rcv_buf > 0)
1265                                 options.hpn_buffer_size = MIN(options.tcp_rcv_buf, options.hpn_buffer_size);
1266                 }
1267
1268         }
1269
1270         debug("Final hpn_buffer_size = %d", options.hpn_buffer_size);
1271
1272         window = options.hpn_buffer_size;
1273
1274         packetmax = CHAN_SES_PACKET_DEFAULT;
1275         if (tty_flag) {
1276                 window = 4*CHAN_SES_PACKET_DEFAULT;
1277                 window >>= 1;
1278                 packetmax >>= 1;
1279         }
1280         c = channel_new(
1281             "session", SSH_CHANNEL_OPENING, in, out, err,
1282             window, packetmax, CHAN_EXTENDED_WRITE,
1283             "client-session", /*nonblock*/0);
1284         if ((options.tcp_rcv_buf_poll > 0) && (!options.hpn_disabled)) {
1285                 c->dynamic_window = 1;
1286                 debug ("Enabled Dynamic Window Scaling\n");
1287         }
1288         debug3("ssh_session2_open: channel_new: %d", c->self);
1289
1290         channel_send_open(c->self);
1291         if (!no_shell_flag)
1292                 channel_register_confirm(c->self, ssh_session2_setup, NULL);
1293
1294         return c->self;
1295 }
1296
1297 static int
1298 ssh_session2(void)
1299 {
1300         int id = -1;
1301
1302         /* XXX should be pre-session */
1303         ssh_init_forwarding();
1304         ssh_control_listener();
1305
1306         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1307                 id = ssh_session2_open();
1308
1309         /* Execute a local command */
1310         if (options.local_command != NULL &&
1311             options.permit_local_command)
1312                 ssh_local_cmd(options.local_command);
1313
1314         /* If requested, let ssh continue in the background. */
1315         if (fork_after_authentication_flag)
1316                 if (daemon(1, 1) < 0)
1317                         fatal("daemon() failed: %.200s", strerror(errno));
1318
1319         return client_loop(tty_flag, tty_flag ?
1320             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1321 }
1322
1323 static void
1324 load_public_identity_files(void)
1325 {
1326         char *filename, *cp, thishost[NI_MAXHOST];
1327         int i = 0;
1328         Key *public;
1329         struct passwd *pw;
1330 #ifdef SMARTCARD
1331         Key **keys;
1332
1333         if (options.smartcard_device != NULL &&
1334             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1335             (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL) {
1336                 int count = 0;
1337                 for (i = 0; keys[i] != NULL; i++) {
1338                         count++;
1339                         memmove(&options.identity_files[1], &options.identity_files[0],
1340                             sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1));
1341                         memmove(&options.identity_keys[1], &options.identity_keys[0],
1342                             sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1));
1343                         options.num_identity_files++;
1344                         options.identity_keys[0] = keys[i];
1345                         options.identity_files[0] = sc_get_key_label(keys[i]);
1346                 }
1347                 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES)
1348                         options.num_identity_files = SSH_MAX_IDENTITY_FILES;
1349                 i = count;
1350                 xfree(keys);
1351         }
1352 #endif /* SMARTCARD */
1353         if ((pw = getpwuid(original_real_uid)) == NULL)
1354                 fatal("load_public_identity_files: getpwuid failed");
1355         if (gethostname(thishost, sizeof(thishost)) == -1)
1356                 fatal("load_public_identity_files: gethostname: %s",
1357                     strerror(errno));
1358         for (; i < options.num_identity_files; i++) {
1359                 cp = tilde_expand_filename(options.identity_files[i],
1360                     original_real_uid);
1361                 filename = percent_expand(cp, "d", pw->pw_dir,
1362                     "u", pw->pw_name, "l", thishost, "h", host,
1363                     "r", options.user, (char *)NULL);
1364                 xfree(cp);
1365                 public = key_load_public(filename, NULL);
1366                 debug("identity file %s type %d", filename,
1367                     public ? public->type : -1);
1368                 xfree(options.identity_files[i]);
1369                 options.identity_files[i] = filename;
1370                 options.identity_keys[i] = public;
1371         }
1372 }
1373
1374 static void
1375 control_client_sighandler(int signo)
1376 {
1377         control_client_terminate = signo;
1378 }
1379
1380 static void
1381 control_client_sigrelay(int signo)
1382 {
1383         if (control_server_pid > 1)
1384                 kill(control_server_pid, signo);
1385 }
1386
1387 static int
1388 env_permitted(char *env)
1389 {
1390         int i, ret;
1391         char name[1024], *cp;
1392
1393         if ((cp = strchr(env, '=')) == NULL || cp == env)
1394                 return (0);
1395         ret = snprintf(name, sizeof(name), "%.*s", (int)(cp - env), env);
1396         if (ret <= 0 || (size_t)ret >= sizeof(name))
1397                 fatal("env_permitted: name '%.100s...' too long", env);
1398
1399         for (i = 0; i < options.num_send_env; i++)
1400                 if (match_pattern(name, options.send_env[i]))
1401                         return (1);
1402
1403         return (0);
1404 }
1405
1406 static void
1407 control_client(const char *path)
1408 {
1409         struct sockaddr_un addr;
1410         int i, r, fd, sock, exitval, num_env, addr_len;
1411         Buffer m;
1412         char *term;
1413         extern char **environ;
1414         u_int  flags;
1415
1416         if (mux_command == 0)
1417                 mux_command = SSHMUX_COMMAND_OPEN;
1418
1419         switch (options.control_master) {
1420         case SSHCTL_MASTER_AUTO:
1421         case SSHCTL_MASTER_AUTO_ASK:
1422                 debug("auto-mux: Trying existing master");
1423                 /* FALLTHROUGH */
1424         case SSHCTL_MASTER_NO:
1425                 break;
1426         default:
1427                 return;
1428         }
1429
1430         memset(&addr, '\0', sizeof(addr));
1431         addr.sun_family = AF_UNIX;
1432         addr_len = offsetof(struct sockaddr_un, sun_path) +
1433             strlen(path) + 1;
1434
1435         if (strlcpy(addr.sun_path, path,
1436             sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
1437                 fatal("ControlPath too long");
1438
1439         if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
1440                 fatal("%s socket(): %s", __func__, strerror(errno));
1441
1442         if (connect(sock, (struct sockaddr *)&addr, addr_len) == -1) {
1443                 if (mux_command != SSHMUX_COMMAND_OPEN) {
1444                         fatal("Control socket connect(%.100s): %s", path,
1445                             strerror(errno));
1446                 }
1447                 if (errno == ENOENT)
1448                         debug("Control socket \"%.100s\" does not exist", path);
1449                 else {
1450                         error("Control socket connect(%.100s): %s", path,
1451                             strerror(errno));
1452                 }
1453                 close(sock);
1454                 return;
1455         }
1456
1457         if (stdin_null_flag) {
1458                 if ((fd = open(_PATH_DEVNULL, O_RDONLY)) == -1)
1459                         fatal("open(/dev/null): %s", strerror(errno));
1460                 if (dup2(fd, STDIN_FILENO) == -1)
1461                         fatal("dup2: %s", strerror(errno));
1462                 if (fd > STDERR_FILENO)
1463                         close(fd);
1464         }
1465
1466         term = getenv("TERM");
1467
1468         flags = 0;
1469         if (tty_flag)
1470                 flags |= SSHMUX_FLAG_TTY;
1471         if (subsystem_flag)
1472                 flags |= SSHMUX_FLAG_SUBSYS;
1473         if (options.forward_x11)
1474                 flags |= SSHMUX_FLAG_X11_FWD;
1475         if (options.forward_agent)
1476                 flags |= SSHMUX_FLAG_AGENT_FWD;
1477         if (options.num_local_forwards > 0)
1478                 flags |= SSHMUX_FLAG_PORTFORWARD;
1479         buffer_init(&m);
1480
1481         /* Send our command to server */
1482         buffer_put_int(&m, mux_command);
1483         buffer_put_int(&m, flags);
1484         if (options.num_local_forwards > 0)
1485         {
1486                 if (options.local_forwards[0].listen_host == NULL)
1487                         buffer_put_string(&m,"LOCALHOST",11);
1488                 else
1489                         buffer_put_string(&m,options.local_forwards[0].listen_host,512);
1490                 buffer_put_int(&m,options.local_forwards[0].listen_port);
1491                 buffer_put_string(&m,options.local_forwards[0].connect_host,512);
1492                 buffer_put_int(&m,options.local_forwards[0].connect_port);
1493         }
1494         if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1)
1495                 fatal("%s: msg_send", __func__);
1496         buffer_clear(&m);
1497
1498         /* Get authorisation status and PID of controlee */
1499         if (ssh_msg_recv(sock, &m) == -1)
1500                 fatal("%s: msg_recv", __func__);
1501         if (buffer_get_char(&m) != SSHMUX_VER)
1502                 fatal("%s: wrong version", __func__);
1503         if (buffer_get_int(&m) != 1)
1504                 fatal("Connection to master denied");
1505         control_server_pid = buffer_get_int(&m);
1506
1507         buffer_clear(&m);
1508
1509         switch (mux_command) {
1510         case SSHMUX_COMMAND_ALIVE_CHECK:
1511                 fprintf(stderr, "Master running (pid=%d)\r\n",
1512                     control_server_pid);
1513                 exit(0);
1514         case SSHMUX_COMMAND_TERMINATE:
1515                 fprintf(stderr, "Exit request sent.\r\n");
1516                 exit(0);
1517         case SSHMUX_COMMAND_OPEN:
1518                 /* continue below */
1519                 break;
1520         default:
1521                 fatal("silly mux_command %d", mux_command);
1522         }
1523
1524         /* SSHMUX_COMMAND_OPEN */
1525         buffer_put_cstring(&m, term ? term : "");
1526         buffer_append(&command, "\0", 1);
1527         buffer_put_cstring(&m, buffer_ptr(&command));
1528
1529         if (options.num_send_env == 0 || environ == NULL) {
1530                 buffer_put_int(&m, 0);
1531         } else {
1532                 /* Pass environment */
1533                 num_env = 0;
1534                 for (i = 0; environ[i] != NULL; i++)
1535                         if (env_permitted(environ[i]))
1536                                 num_env++; /* Count */
1537
1538                 buffer_put_int(&m, num_env);
1539
1540                 for (i = 0; environ[i] != NULL && num_env >= 0; i++)
1541                         if (env_permitted(environ[i])) {
1542                                 num_env--;
1543                                 buffer_put_cstring(&m, environ[i]);
1544                         }
1545         }
1546
1547         if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1)
1548                 fatal("%s: msg_send", __func__);
1549
1550         mm_send_fd(sock, STDIN_FILENO);
1551         mm_send_fd(sock, STDOUT_FILENO);
1552         mm_send_fd(sock, STDERR_FILENO);
1553
1554         /* Wait for reply, so master has a chance to gather ttymodes */
1555         buffer_clear(&m);
1556         if (ssh_msg_recv(sock, &m) == -1)
1557                 fatal("%s: msg_recv", __func__);
1558         if (buffer_get_char(&m) != SSHMUX_VER)
1559                 fatal("%s: wrong version", __func__);
1560         buffer_free(&m);
1561
1562         signal(SIGHUP, control_client_sighandler);
1563         signal(SIGINT, control_client_sighandler);
1564         signal(SIGTERM, control_client_sighandler);
1565         signal(SIGWINCH, control_client_sigrelay);
1566
1567         if (tty_flag)
1568                 enter_raw_mode();
1569
1570         /* Stick around until the controlee closes the client_fd */
1571         exitval = 0;
1572         for (;!control_client_terminate;) {
1573                 r = read(sock, &exitval, sizeof(exitval));
1574                 if (r == 0) {
1575                         debug2("Received EOF from master");
1576                         break;
1577                 }
1578                 if (r > 0)
1579                         debug2("Received exit status from master %d", exitval);
1580                 if (r == -1 && errno != EINTR)
1581                         fatal("%s: read %s", __func__, strerror(errno));
1582         }
1583
1584         if (control_client_terminate)
1585                 debug2("Exiting on signal %d", control_client_terminate);
1586
1587         close(sock);
1588
1589         leave_raw_mode();
1590
1591         if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET)
1592                 fprintf(stderr, "Connection to master closed.\r\n");
1593
1594         exit(exitval);
1595 }