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_pathnames();
 224         init_rng();
 225
 226         /*
 227          * Save the original real uid.  It will be needed later (uid-swapping
 228          * may clobber the real uid).
 229          */
 230         original_real_uid = getuid();
 231         original_effective_uid = geteuid();
 232
 233         /*
 234          * Use uid-swapping to give up root privileges for the duration of
 235          * option processing.  We will re-instantiate the rights when we are
 236          * ready to create the privileged port, and will permanently drop
 237          * them when the port has been created (actually, when the connection
 238          * has been made, as we may need to create the port several times).
 239          */
 240         PRIV_END;
 241
 242 #ifdef HAVE_SETRLIMIT
 243         /* If we are installed setuid root be careful to not drop core. */
 244         if (original_real_uid != original_effective_uid) {
 245                 struct rlimit rlim;
 246                 rlim.rlim_cur = rlim.rlim_max = 0;
 247                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 248                         fatal("setrlimit failed: %.100s", strerror(errno));
 249         }
 250 #endif
 251         /* Get user data. */
 252         pw = getpwuid(original_real_uid);
 253         if (!pw) {
 254                 logit("You don't exist, go away!");
 255                 exit(255);
 256         }
 257         /* Take a copy of the returned structure. */
 258         pw = pwcopy(pw);
 259
 260         /*
 261          * Set our umask to something reasonable, as some files are created
 262          * with the default umask.  This will make them world-readable but
 263          * writable only by the owner, which is ok for all files for which we
 264          * don't set the modes explicitly.
 265          */
 266         umask(022);
 267
 268         /* Initialize option structure to indicate that no values have been set. */
 269         initialize_options(&options);
 270
 271         /* Parse command-line arguments. */
 272         host = NULL;
 273
 274  again:
 275         while ((opt = getopt(ac, av,
 276             "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:MNO:PR:S:TVw:XY")) != -1) {
 277                 switch (opt) {
 278                 case '1':
 279                         options.protocol = SSH_PROTO_1;
 280                         break;
 281                 case '2':
 282                         options.protocol = SSH_PROTO_2;
 283                         break;
 284                 case '4':
 285                         options.address_family = AF_INET;
 286                         break;
 287                 case '6':
 288                         options.address_family = AF_INET6;
 289                         break;
 290                 case 'n':
 291                         stdin_null_flag = 1;
 292                         break;
 293                 case 'f':
 294                         fork_after_authentication_flag = 1;
 295                         stdin_null_flag = 1;
 296                         break;
 297                 case 'x':
 298                         options.forward_x11 = 0;
 299                         break;
 300                 case 'X':
 301                         options.forward_x11 = 1;
 302                         break;
 303                 case 'Y':
 304                         options.forward_x11 = 1;
 305                         options.forward_x11_trusted = 1;
 306                         break;
 307                 case 'g':
 308                         options.gateway_ports = 1;
 309                         break;
 310                 case 'O':
 311                         if (strcmp(optarg, "check") == 0)
 312                                 mux_command = SSHMUX_COMMAND_ALIVE_CHECK;
 313                         else if (strcmp(optarg, "exit") == 0)
 314                                 mux_command = SSHMUX_COMMAND_TERMINATE;
 315                         else
 316                                 fatal("Invalid multiplex command.");
 317                         break;
 318                 case 'P':       /* deprecated */
 319                         options.use_privileged_port = 0;
 320                         break;
 321                 case 'a':
 322                         options.forward_agent = 0;
 323                         break;
 324                 case 'A':
 325                         options.forward_agent = 1;
 326                         break;
 327                 case 'k':
 328                         options.gss_deleg_creds = 0;
 329                         break;
 330                 case 'i':
 331                         if (stat(optarg, &st) < 0) {
 332                                 fprintf(stderr, "Warning: Identity file %s "
 333                                     "not accessible: %s.\n", optarg,
 334                                     strerror(errno));
 335                                 break;
 336                         }
 337                         if (options.num_identity_files >=
 338                             SSH_MAX_IDENTITY_FILES)
 339                                 fatal("Too many identity files specified "
 340                                     "(max %d)", SSH_MAX_IDENTITY_FILES);
 341                         options.identity_files[options.num_identity_files++] =
 342                             xstrdup(optarg);
 343                         break;
 344                 case 'I':
 345 #ifdef SMARTCARD
 346                         options.smartcard_device = xstrdup(optarg);
 347 #else
 348                         fprintf(stderr, "no support for smartcards.\n");
 349 #endif
 350                         break;
 351                 case 't':
 352                         if (tty_flag)
 353                                 force_tty_flag = 1;
 354                         tty_flag = 1;
 355                         break;
 356                 case 'v':
 357                         if (debug_flag == 0) {
 358                                 debug_flag = 1;
 359                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 360                         } else {
 361                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
 362                                         options.log_level++;
 363                                 break;
 364                         }
 365                         /* FALLTHROUGH */
 366                 case 'V':
 367                         fprintf(stderr, "%s, %s\n",
 368                             SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
 369                         if (opt == 'V')
 370                                 exit(0);
 371                         break;
 372                 case 'w':
 373                         if (options.tun_open == -1)
 374                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 375                         options.tun_local = a2tun(optarg, &options.tun_remote);
 376                         if (options.tun_local == SSH_TUNID_ERR) {
 377                                 fprintf(stderr, "Bad tun device '%s'\n", optarg);
 378                                 exit(255);
 379                         }
 380                         break;
 381                 case 'q':
 382                         options.log_level = SYSLOG_LEVEL_QUIET;
 383                         break;
 384                 case 'e':
 385                         if (optarg[0] == '^' && optarg[2] == 0 &&
 386                             (u_char) optarg[1] >= 64 &&
 387                             (u_char) optarg[1] < 128)
 388                                 options.escape_char = (u_char) optarg[1] & 31;
 389                         else if (strlen(optarg) == 1)
 390                                 options.escape_char = (u_char) optarg[0];
 391                         else if (strcmp(optarg, "none") == 0)
 392                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 393                         else {
 394                                 fprintf(stderr, "Bad escape character '%s'.\n",
 395                                     optarg);
 396                                 exit(255);
 397                         }
 398                         break;
 399                 case 'c':
 400                         if (ciphers_valid(optarg)) {
 401                                 /* SSH2 only */
 402                                 options.ciphers = xstrdup(optarg);
 403                                 options.cipher = SSH_CIPHER_INVALID;
 404                         } else {
 405                                 /* SSH1 only */
 406                                 options.cipher = cipher_number(optarg);
 407                                 if (options.cipher == -1) {
 408                                         fprintf(stderr,
 409                                             "Unknown cipher type '%s'\n",
 410                                             optarg);
 411                                         exit(255);
 412                                 }
 413                                 if (options.cipher == SSH_CIPHER_3DES)
 414                                         options.ciphers = "3des-cbc";
 415                                 else if (options.cipher == SSH_CIPHER_BLOWFISH)
 416                                         options.ciphers = "blowfish-cbc";
 417                                 else
 418                                         options.ciphers = (char *)-1;
 419                         }
 420                         break;
 421                 case 'm':
 422                         if (mac_valid(optarg))
 423                                 options.macs = xstrdup(optarg);
 424                         else {
 425                                 fprintf(stderr, "Unknown mac type '%s'\n",
 426                                     optarg);
 427                                 exit(255);
 428                         }
 429                         break;
 430                 case 'M':
 431                         if (options.control_master == SSHCTL_MASTER_YES)
 432                                 options.control_master = SSHCTL_MASTER_ASK;
 433                         else
 434                                 options.control_master = SSHCTL_MASTER_YES;
 435                         break;
 436                 case 'p':
 437                         options.port = a2port(optarg);
 438                         if (options.port == 0) {
 439                                 fprintf(stderr, "Bad port '%s'\n", optarg);
 440                                 exit(255);
 441                         }
 442                         break;
 443                 case 'l':
 444                         options.user = optarg;
 445                         break;
 446
 447                 case 'L':
 448                         if (parse_forward(&fwd, optarg))
 449                                 add_local_forward(&options, &fwd);
 450                         else {
 451                                 fprintf(stderr,
 452                                     "Bad local forwarding specification '%s'\n",
 453                                     optarg);
 454                                 exit(255);
 455                         }
 456                         break;
 457
 458                 case 'R':
 459                         if (parse_forward(&fwd, optarg)) {
 460                                 add_remote_forward(&options, &fwd);
 461                         } else {
 462                                 fprintf(stderr,
 463                                     "Bad remote forwarding specification "
 464                                     "'%s'\n", optarg);
 465                                 exit(255);
 466                         }
 467                         break;
 468
 469                 case 'D':
 470                         cp = p = xstrdup(optarg);
 471                         memset(&fwd, '\0', sizeof(fwd));
 472                         fwd.connect_host = "socks";
 473                         if ((fwd.listen_host = hpdelim(&cp)) == NULL) {
 474                                 fprintf(stderr, "Bad dynamic forwarding "
 475                                     "specification '%.100s'\n", optarg);
 476                                 exit(255);
 477                         }
 478                         if (cp != NULL) {
 479                                 fwd.listen_port = a2port(cp);
 480                                 fwd.listen_host = cleanhostname(fwd.listen_host);
 481                         } else {
 482                                 fwd.listen_port = a2port(fwd.listen_host);
 483                                 fwd.listen_host = NULL;
 484                         }
 485
 486                         if (fwd.listen_port == 0) {
 487                                 fprintf(stderr, "Bad dynamic port '%s'\n",
 488                                     optarg);
 489                                 exit(255);
 490                         }
 491                         add_local_forward(&options, &fwd);
 492                         xfree(p);
 493                         break;
 494
 495                 case 'C':
 496                         options.compression = 1;
 497                         break;
 498                 case 'N':
 499                         no_shell_flag = 1;
 500                         no_tty_flag = 1;
 501                         break;
 502                 case 'o':
 503                         dummy = 1;
 504                         line = xstrdup(optarg);
 505                         if (process_config_line(&options, host ? host : "",
 506                             line, "command-line", 0, &dummy) != 0)
 507                                 exit(255);
 508                         xfree(line);
 509                         break;
 510                 case 'T':
 511                         no_tty_flag = 1;
 512                         /* ensure that the user doesn't try to backdoor a */
 513                         /* null cipher switch on an interactive session */
 514                         /* so explicitly disable it no matter what */
 515                         options.none_switch=0;
 516                         break;
 517                 case 's':
 518                         subsystem_flag = 1;
 519                         break;
 520                 case 'S':
 521                         if (options.control_path != NULL)
 522                                 free(options.control_path);
 523                         options.control_path = xstrdup(optarg);
 524                         break;
 525                 case 'b':
 526                         options.bind_address = optarg;
 527                         break;
 528                 case 'F':
 529                         config = optarg;
 530                         break;
 531                 default:
 532                         usage();
 533                 }
 534         }
 535
 536         ac -= optind;
 537         av += optind;
 538
 539         if (ac > 0 && !host && **av != '-') {
 540                 if (strrchr(*av, '@')) {
 541                         p = xstrdup(*av);
 542                         cp = strrchr(p, '@');
 543                         if (cp == NULL || cp == p)
 544                                 usage();
 545                         options.user = p;
 546                         *cp = '\0';
 547                         host = ++cp;
 548                 } else
 549                         host = *av;
 550                 if (ac > 1) {
 551                         optind = optreset = 1;
 552                         goto again;
 553                 }
 554                 ac--, av++;
 555         }
 556
 557         /* Check that we got a host name. */
 558         if (!host)
 559                 usage();
 560
 561         SSLeay_add_all_algorithms();
 562         ERR_load_crypto_strings();
 563
 564         /* Initialize the command to execute on remote host. */
 565         buffer_init(&command);
 566
 567         /*
 568          * Save the command to execute on the remote host in a buffer. There
 569          * is no limit on the length of the command, except by the maximum
 570          * packet size.  Also sets the tty flag if there is no command.
 571          */
 572         if (!ac) {
 573                 /* No command specified - execute shell on a tty. */
 574                 tty_flag = 1;
 575                 if (subsystem_flag) {
 576                         fprintf(stderr,
 577                             "You must specify a subsystem to invoke.\n");
 578                         usage();
 579                 }
 580         } else {
 581                 /* A command has been specified.  Store it into the buffer. */
 582                 for (i = 0; i < ac; i++) {
 583                         if (i)
 584                                 buffer_append(&command, " ", 1);
 585                         buffer_append(&command, av[i], strlen(av[i]));
 586                 }
 587         }
 588
 589         /* Cannot fork to background if no command. */
 590         if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag)
 591                 fatal("Cannot fork into background without a command to execute.");
 592
 593         /* Allocate a tty by default if no command specified. */
 594         if (buffer_len(&command) == 0)
 595                 tty_flag = 1;
 596
 597         /* Force no tty */
 598         if (no_tty_flag)
 599                 tty_flag = 0;
 600         /* Do not allocate a tty if stdin is not a tty. */
 601         if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) {
 602                 if (tty_flag)
 603                         logit("Pseudo-terminal will not be allocated because stdin is not a terminal.");
 604                 tty_flag = 0;
 605         }
 606
 607         /*
 608          * Initialize "log" output.  Since we are the client all output
 609          * actually goes to stderr.
 610          */
 611         log_init(av[0], options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
 612             SYSLOG_FACILITY_USER, 1);
 613
 614         /*
 615          * Read per-user configuration file.  Ignore the system wide config
 616          * file if the user specifies a config file on the command line.
 617          */
 618         if (config != NULL) {
 619                 if (!read_config_file(config, host, &options, 0))
 620                         fatal("Can't open user config file %.100s: "
 621                             "%.100s", config, strerror(errno));
 622         } else  {
 623             /*
 624              * Since the config file parsing code aborts if it sees
 625              * options it doesn't recognize, allow users to put
 626              * options specific to compile-time add-ons in alternate
 627              * config files so their primary config file will
 628              * interoperate SSH versions that don't support those
 629              * options.
 630              */
 631 #ifdef GSSAPI
 632                 snprintf(buf, sizeof buf, "%.100s/%.100s.gssapi", pw->pw_dir,
 633                     _PATH_SSH_USER_CONFFILE);
 634                 (void)read_config_file(buf, host, &options, 1);
 635 #ifdef GSI
 636                 snprintf(buf, sizeof buf, "%.100s/%.100s.gsi", pw->pw_dir,
 637                     _PATH_SSH_USER_CONFFILE);
 638                 (void)read_config_file(buf, host, &options, 1);
 639 #endif
 640 #if defined(KRB5)
 641                 snprintf(buf, sizeof buf, "%.100s/%.100s.krb", pw->pw_dir,
 642                     _PATH_SSH_USER_CONFFILE);
 643                 (void)read_config_file(buf, host, &options, 1);
 644 #endif
 645 #endif
 646                 snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir,
 647                     _PATH_SSH_USER_CONFFILE);
 648                 (void)read_config_file(buf, host, &options, 1);
 649
 650                 /* Read systemwide configuration file after use config. */
 651                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host,
 652                     &options, 0);
 653         }
 654
 655         /* Fill configuration defaults. */
 656         fill_default_options(&options);
 657
 658         channel_set_af(options.address_family);
 659
 660         /* reinit */
 661         log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1);
 662
 663         seed_rng();
 664
 665         if (options.user == NULL) {
 666                 options.user = xstrdup(pw->pw_name);
 667                 options.implicit = 1;
 668         }
 669         else options.implicit = 0;
 670
 671         if (options.hostname != NULL)
 672                 host = options.hostname;
 673
 674         /* force lowercase for hostkey matching */
 675         if (options.host_key_alias != NULL) {
 676                 for (p = options.host_key_alias; *p; p++)
 677                         if (isupper(*p))
 678                                 *p = (char)tolower(*p);
 679         }
 680
 681         /* Get default port if port has not been set. */
 682         if (options.port == 0) {
 683                 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
 684                 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT;
 685         }
 686
 687         if (options.proxy_command != NULL &&
 688             strcmp(options.proxy_command, "none") == 0)
 689                 options.proxy_command = NULL;
 690         if (options.control_path != NULL &&
 691             strcmp(options.control_path, "none") == 0)
 692                 options.control_path = NULL;
 693
 694         if (options.control_path != NULL) {
 695                 char thishost[NI_MAXHOST];
 696
 697                 if (gethostname(thishost, sizeof(thishost)) == -1)
 698                         fatal("gethostname: %s", strerror(errno));
 699                 snprintf(buf, sizeof(buf), "%d", options.port);
 700                 cp = tilde_expand_filename(options.control_path,
 701                     original_real_uid);
 702                 options.control_path = percent_expand(cp, "p", buf, "h", host,
 703                     "r", options.user, "l", thishost, (char *)NULL);
 704                 xfree(cp);
 705         }
 706         if (mux_command != 0 && options.control_path == NULL)
 707                 fatal("No ControlPath specified for \"-O\" command");
 708         if (options.control_path != NULL)
 709                 control_client(options.control_path);
 710
 711         /* Open a connection to the remote host. */
 712         if (ssh_connect(host, &hostaddr, options.port,
 713             options.address_family, options.connection_attempts,
 714 #ifdef HAVE_CYGWIN
 715             options.use_privileged_port,
 716 #else
 717             original_effective_uid == 0 && options.use_privileged_port,
 718 #endif
 719             options.proxy_command) != 0)
 720                 exit(255);
 721
 722         /*
 723          * If we successfully made the connection, load the host private key
 724          * in case we will need it later for combined rsa-rhosts
 725          * authentication. This must be done before releasing extra
 726          * privileges, because the file is only readable by root.
 727          * If we cannot access the private keys, load the public keys
 728          * instead and try to execute the ssh-keysign helper instead.
 729          */
 730         sensitive_data.nkeys = 0;
 731         sensitive_data.keys = NULL;
 732         sensitive_data.external_keysign = 0;
 733         if (options.rhosts_rsa_authentication ||
 734             options.hostbased_authentication) {
 735                 sensitive_data.nkeys = 3;
 736                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
 737                     sizeof(Key));
 738
 739                 PRIV_START;
 740                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
 741                     _PATH_HOST_KEY_FILE, "", NULL, NULL);
 742                 sensitive_data.keys[1] = key_load_private_type(KEY_DSA,
 743                     _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
 744                 sensitive_data.keys[2] = key_load_private_type(KEY_RSA,
 745                     _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
 746                 PRIV_END;
 747
 748                 if (options.hostbased_authentication == 1 &&
 749                     sensitive_data.keys[0] == NULL &&
 750                     sensitive_data.keys[1] == NULL &&
 751                     sensitive_data.keys[2] == NULL) {
 752                         sensitive_data.keys[1] = key_load_public(
 753                             _PATH_HOST_DSA_KEY_FILE, NULL);
 754                         sensitive_data.keys[2] = key_load_public(
 755                             _PATH_HOST_RSA_KEY_FILE, NULL);
 756                         sensitive_data.external_keysign = 1;
 757                 }
 758         }
 759         /*
 760          * Get rid of any extra privileges that we may have.  We will no
 761          * longer need them.  Also, extra privileges could make it very hard
 762          * to read identity files and other non-world-readable files from the
 763          * user's home directory if it happens to be on a NFS volume where
 764          * root is mapped to nobody.
 765          */
 766         if (original_effective_uid == 0) {
 767                 PRIV_START;
 768                 permanently_set_uid(pw);
 769         }
 770
 771         /*
 772          * Now that we are back to our own permissions, create ~/.ssh
 773          * directory if it doesn't already exist.
 774          */
 775         snprintf(buf, sizeof buf, "%.100s%s%.100s", pw->pw_dir, strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
 776         if (stat(buf, &st) < 0)
 777                 if (mkdir(buf, 0700) < 0)
 778                         error("Could not create directory '%.200s'.", buf);
 779
 780         /* load options.identity_files */
 781         load_public_identity_files();
 782
 783         /* Expand ~ in known host file names. */
 784         /* XXX mem-leaks: */
 785         options.system_hostfile =
 786             tilde_expand_filename(options.system_hostfile, original_real_uid);
 787         options.user_hostfile =
 788             tilde_expand_filename(options.user_hostfile, original_real_uid);
 789         options.system_hostfile2 =
 790             tilde_expand_filename(options.system_hostfile2, original_real_uid);
 791         options.user_hostfile2 =
 792             tilde_expand_filename(options.user_hostfile2, original_real_uid);
 793
 794         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
 795
 796         /* Log into the remote system.  This never returns if the login fails. */
 797         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, pw);
 798
 799         /* We no longer need the private host keys.  Clear them now. */
 800         if (sensitive_data.nkeys != 0) {
 801                 for (i = 0; i < sensitive_data.nkeys; i++) {
 802                         if (sensitive_data.keys[i] != NULL) {
 803                                 /* Destroys contents safely */
 804                                 debug3("clear hostkey %d", i);
 805                                 key_free(sensitive_data.keys[i]);
 806                                 sensitive_data.keys[i] = NULL;
 807                         }
 808                 }
 809                 xfree(sensitive_data.keys);
 810         }
 811         for (i = 0; i < options.num_identity_files; i++) {
 812                 if (options.identity_files[i]) {
 813                         xfree(options.identity_files[i]);
 814                         options.identity_files[i] = NULL;
 815                 }
 816                 if (options.identity_keys[i]) {
 817                         key_free(options.identity_keys[i]);
 818                         options.identity_keys[i] = NULL;
 819                 }
 820         }
 821
 822         exit_status = compat20 ? ssh_session2() : ssh_session();
 823         packet_close();
 824
 825         if (options.control_path != NULL && control_fd != -1)
 826                 unlink(options.control_path);
 827
 828         /*
 829          * Send SIGHUP to proxy command if used. We don't wait() in
 830          * case it hangs and instead rely on init to reap the child
 831          */
 832         if (proxy_command_pid > 1)
 833                 kill(proxy_command_pid, SIGHUP);
 834
 835         return exit_status;
 836 }
 837
 838 static void
 839 ssh_init_forwarding(void)
 840 {
 841         int success = 0;
 842         int i;
 843
 844         /* Initiate local TCP/IP port forwardings. */
 845         for (i = 0; i < options.num_local_forwards; i++) {
 846                 debug("Local connections to %.200s:%d forwarded to remote "
 847                     "address %.200s:%d",
 848                     (options.local_forwards[i].listen_host == NULL) ?
 849                     (options.gateway_ports ? "*" : "LOCALHOST") :
 850                     options.local_forwards[i].listen_host,
 851                     options.local_forwards[i].listen_port,
 852                     options.local_forwards[i].connect_host,
 853                     options.local_forwards[i].connect_port);
 854                 success += channel_setup_local_fwd_listener(
 855                     options.local_forwards[i].listen_host,
 856                     options.local_forwards[i].listen_port,
 857                     options.local_forwards[i].connect_host,
 858                     options.local_forwards[i].connect_port,
 859                     options.gateway_ports, options.hpn_disabled,
 860                     options.hpn_buffer_size);
 861         }
 862         if (i > 0 && success != i && options.exit_on_forward_failure)
 863                 fatal("Could not request local forwarding.");
 864         if (i > 0 && success == 0)
 865                 error("Could not request local forwarding.");
 866
 867         /* Initiate remote TCP/IP port forwardings. */
 868         for (i = 0; i < options.num_remote_forwards; i++) {
 869                 debug("Remote connections from %.200s:%d forwarded to "
 870                     "local address %.200s:%d",
 871                     (options.remote_forwards[i].listen_host == NULL) ?
 872                     "LOCALHOST" : options.remote_forwards[i].listen_host,
 873                     options.remote_forwards[i].listen_port,
 874                     options.remote_forwards[i].connect_host,
 875                     options.remote_forwards[i].connect_port);
 876                 if (channel_request_remote_forwarding(
 877                     options.remote_forwards[i].listen_host,
 878                     options.remote_forwards[i].listen_port,
 879                     options.remote_forwards[i].connect_host,
 880                     options.remote_forwards[i].connect_port) < 0) {
 881                         if (options.exit_on_forward_failure)
 882                                 fatal("Could not request remote forwarding.");
 883                         else
 884                                 logit("Warning: Could not request remote "
 885                                     "forwarding.");
 886                 }
 887         }
 888 }
 889
 890 static void
 891 check_agent_present(void)
 892 {
 893         if (options.forward_agent) {
 894                 /* Clear agent forwarding if we don't have an agent. */
 895                 if (!ssh_agent_present())
 896                         options.forward_agent = 0;
 897         }
 898 }
 899
 900 static int
 901 ssh_session(void)
 902 {
 903         int type;
 904         int interactive = 0;
 905         int have_tty = 0;
 906         struct winsize ws;
 907         char *cp;
 908         const char *display;
 909
 910         /* Enable compression if requested. */
 911         if (options.compression) {
 912                 debug("Requesting compression at level %d.", options.compression_level);
 913
 914                 if (options.compression_level < 1 || options.compression_level > 9)
 915                         fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
 916
 917                 /* Send the request. */
 918                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
 919                 packet_put_int(options.compression_level);
 920                 packet_send();
 921                 packet_write_wait();
 922                 type = packet_read();
 923                 if (type == SSH_SMSG_SUCCESS)
 924                         packet_start_compression(options.compression_level);
 925                 else if (type == SSH_SMSG_FAILURE)
 926                         logit("Warning: Remote host refused compression.");
 927                 else
 928                         packet_disconnect("Protocol error waiting for compression response.");
 929         }
 930         /* Allocate a pseudo tty if appropriate. */
 931         if (tty_flag) {
 932                 debug("Requesting pty.");
 933
 934                 /* Start the packet. */
 935                 packet_start(SSH_CMSG_REQUEST_PTY);
 936
 937                 /* Store TERM in the packet.  There is no limit on the
 938                    length of the string. */
 939                 cp = getenv("TERM");
 940                 if (!cp)
 941                         cp = "";
 942                 packet_put_cstring(cp);
 943
 944                 /* Store window size in the packet. */
 945                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
 946                         memset(&ws, 0, sizeof(ws));
 947                 packet_put_int((u_int)ws.ws_row);
 948                 packet_put_int((u_int)ws.ws_col);
 949                 packet_put_int((u_int)ws.ws_xpixel);
 950                 packet_put_int((u_int)ws.ws_ypixel);
 951
 952                 /* Store tty modes in the packet. */
 953                 tty_make_modes(fileno(stdin), NULL);
 954
 955                 /* Send the packet, and wait for it to leave. */
 956                 packet_send();
 957                 packet_write_wait();
 958
 959                 /* Read response from the server. */
 960                 type = packet_read();
 961                 if (type == SSH_SMSG_SUCCESS) {
 962                         interactive = 1;
 963                         have_tty = 1;
 964                 } else if (type == SSH_SMSG_FAILURE)
 965                         logit("Warning: Remote host failed or refused to allocate a pseudo tty.");
 966                 else
 967                         packet_disconnect("Protocol error waiting for pty request response.");
 968         }
 969         /* Request X11 forwarding if enabled and DISPLAY is set. */
 970         display = getenv("DISPLAY");
 971         if (options.forward_x11 && display != NULL) {
 972                 char *proto, *data;
 973                 /* Get reasonable local authentication information. */
 974                 client_x11_get_proto(display, options.xauth_location,
 975                     options.forward_x11_trusted, &proto, &data);
 976                 /* Request forwarding with authentication spoofing. */
 977                 debug("Requesting X11 forwarding with authentication spoofing.");
 978                 x11_request_forwarding_with_spoofing(0, display, proto, data);
 979
 980                 /* Read response from the server. */
 981                 type = packet_read();
 982                 if (type == SSH_SMSG_SUCCESS) {
 983                         interactive = 1;
 984                 } else if (type == SSH_SMSG_FAILURE) {
 985                         logit("Warning: Remote host denied X11 forwarding.");
 986                 } else {
 987                         packet_disconnect("Protocol error waiting for X11 forwarding");
 988                 }
 989         }
 990         /* Tell the packet module whether this is an interactive session. */
 991         packet_set_interactive(interactive);
 992
 993         /* Request authentication agent forwarding if appropriate. */
 994         check_agent_present();
 995
 996         if (options.forward_agent) {
 997                 debug("Requesting authentication agent forwarding.");
 998                 auth_request_forwarding();
 999
1000                 /* Read response from the server. */
1001                 type = packet_read();
1002                 packet_check_eom();
1003                 if (type != SSH_SMSG_SUCCESS)
1004                         logit("Warning: Remote host denied authentication agent forwarding.");
1005         }
1006
1007         /* Initiate port forwardings. */
1008         ssh_init_forwarding();
1009
1010         /* If requested, let ssh continue in the background. */
1011         if (fork_after_authentication_flag)
1012                 if (daemon(1, 1) < 0)
1013                         fatal("daemon() failed: %.200s", strerror(errno));
1014
1015         /*
1016          * If a command was specified on the command line, execute the
1017          * command now. Otherwise request the server to start a shell.
1018          */
1019         if (buffer_len(&command) > 0) {
1020                 int len = buffer_len(&command);
1021                 if (len > 900)
1022                         len = 900;
1023                 debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command));
1024                 packet_start(SSH_CMSG_EXEC_CMD);
1025                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1026                 packet_send();
1027                 packet_write_wait();
1028         } else {
1029                 debug("Requesting shell.");
1030                 packet_start(SSH_CMSG_EXEC_SHELL);
1031                 packet_send();
1032                 packet_write_wait();
1033         }
1034
1035         /* Enter the interactive session. */
1036         return client_loop(have_tty, tty_flag ?
1037             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1038 }
1039
1040 static void
1041 ssh_subsystem_reply(int type, u_int32_t seq, void *ctxt)
1042 {
1043         int id, len;
1044
1045         id = packet_get_int();
1046         len = buffer_len(&command);
1047         if (len > 900)
1048                 len = 900;
1049         packet_check_eom();
1050         if (type == SSH2_MSG_CHANNEL_FAILURE)
1051                 fatal("Request for subsystem '%.*s' failed on channel %d",
1052                     len, (u_char *)buffer_ptr(&command), id);
1053 }
1054
1055 void
1056 client_global_request_reply_fwd(int type, u_int32_t seq, void *ctxt)
1057 {
1058         int i;
1059
1060         i = client_global_request_id++;
1061         if (i >= options.num_remote_forwards)
1062                 return;
1063         debug("remote forward %s for: listen %d, connect %s:%d",
1064             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1065             options.remote_forwards[i].listen_port,
1066             options.remote_forwards[i].connect_host,
1067             options.remote_forwards[i].connect_port);
1068         if (type == SSH2_MSG_REQUEST_FAILURE) {
1069                 if (options.exit_on_forward_failure)
1070                         fatal("Error: remote port forwarding failed for "
1071                             "listen port %d",
1072                             options.remote_forwards[i].listen_port);
1073                 else
1074                         logit("Warning: remote port forwarding failed for "
1075                             "listen port %d",
1076                             options.remote_forwards[i].listen_port);
1077         }
1078 }
1079
1080 static void
1081 ssh_control_listener(void)
1082 {
1083         struct sockaddr_un addr;
1084         mode_t old_umask;
1085         int addr_len;
1086
1087         if (options.control_path == NULL ||
1088             options.control_master == SSHCTL_MASTER_NO)
1089                 return;
1090
1091         debug("setting up multiplex master socket");
1092
1093         memset(&addr, '\0', sizeof(addr));
1094         addr.sun_family = AF_UNIX;
1095         addr_len = offsetof(struct sockaddr_un, sun_path) +
1096             strlen(options.control_path) + 1;
1097
1098         if (strlcpy(addr.sun_path, options.control_path,
1099             sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
1100                 fatal("ControlPath too long");
1101
1102         if ((control_fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
1103                 fatal("%s socket(): %s", __func__, strerror(errno));
1104
1105         old_umask = umask(0177);
1106         if (bind(control_fd, (struct sockaddr *)&addr, addr_len) == -1) {
1107                 control_fd = -1;
1108                 if (errno == EINVAL || errno == EADDRINUSE)
1109                         fatal("ControlSocket %s already exists",
1110                             options.control_path);
1111                 else
1112                         fatal("%s bind(): %s", __func__, strerror(errno));
1113         }
1114         umask(old_umask);
1115
1116         if (listen(control_fd, 64) == -1)
1117                 fatal("%s listen(): %s", __func__, strerror(errno));
1118
1119         set_nonblock(control_fd);
1120 }
1121
1122 /* request pty/x11/agent/tcpfwd/shell for channel */
1123 static void
1124 ssh_session2_setup(int id, void *arg)
1125 {
1126         extern char **environ;
1127         const char *display;
1128         int interactive = tty_flag;
1129
1130         display = getenv("DISPLAY");
1131         if (options.forward_x11 && display != NULL) {
1132                 char *proto, *data;
1133                 /* Get reasonable local authentication information. */
1134                 client_x11_get_proto(display, options.xauth_location,
1135                     options.forward_x11_trusted, &proto, &data);
1136                 /* Request forwarding with authentication spoofing. */
1137                 debug("Requesting X11 forwarding with authentication spoofing.");
1138                 x11_request_forwarding_with_spoofing(id, display, proto, data);
1139                 interactive = 1;
1140                 /* XXX wait for reply */
1141         }
1142
1143         check_agent_present();
1144         if (options.forward_agent) {
1145                 debug("Requesting authentication agent forwarding.");
1146                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1147                 packet_send();
1148         }
1149
1150         if (options.tun_open != SSH_TUNMODE_NO) {
1151                 Channel *c;
1152                 int fd;
1153
1154                 debug("Requesting tun.");
1155                 if ((fd = tun_open(options.tun_local,
1156                     options.tun_open)) >= 0) {
1157                         if(options.hpn_disabled)
1158                                 c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1,
1159                                     CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1160                                     0, "tun", 1);
1161                         else
1162                                 c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1,
1163                                     options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT,
1164                                     0, "tun", 1);
1165                         c->datagram = 1;
1166 #if defined(SSH_TUN_FILTER)
1167                         if (options.tun_open == SSH_TUNMODE_POINTOPOINT)
1168                                 channel_register_filter(c->self, sys_tun_infilter,
1169                                     sys_tun_outfilter);
1170 #endif
1171                         packet_start(SSH2_MSG_CHANNEL_OPEN);
1172                         packet_put_cstring("tun@openssh.com");
1173                         packet_put_int(c->self);
1174                         packet_put_int(c->local_window_max);
1175                         packet_put_int(c->local_maxpacket);
1176                         packet_put_int(options.tun_open);
1177                         packet_put_int(options.tun_remote);
1178                         packet_send();
1179                 }
1180         }
1181
1182         client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1183             NULL, fileno(stdin), &command, environ, &ssh_subsystem_reply);
1184
1185         packet_set_interactive(interactive);
1186 }
1187
1188 /* open new channel for a session */
1189 static int
1190 ssh_session2_open(void)
1191 {
1192         Channel *c;
1193         int window, packetmax, in, out, err;
1194         int sock;
1195         int socksize;
1196         int socksizelen = sizeof(int);
1197
1198         if (stdin_null_flag) {
1199                 in = open(_PATH_DEVNULL, O_RDONLY);
1200         } else {
1201                 in = dup(STDIN_FILENO);
1202         }
1203         out = dup(STDOUT_FILENO);
1204         err = dup(STDERR_FILENO);
1205
1206         if (in < 0 || out < 0 || err < 0)
1207                 fatal("dup() in/out/err failed");
1208
1209         /* enable nonblocking unless tty */
1210         if (!isatty(in))
1211                 set_nonblock(in);
1212         if (!isatty(out))
1213                 set_nonblock(out);
1214         if (!isatty(err))
1215                 set_nonblock(err);
1216
1217         /* we need to check to see if what they want to do about buffer */
1218         /* sizes here. In a hpn to nonhpn connection we want to limit */
1219         /* the window size to something reasonable in case the far side */
1220         /* has the large window bug. In hpn to hpn connection we want to */
1221         /* use the max window size but allow the user to override it */
1222         /* lastly if they disabled hpn then use the ssh std window size */
1223
1224         /* so why don't we just do a getsockopt() here and set the */
1225         /* ssh window to that? In the case of a autotuning receive */
1226         /* window the window would get stuck at the initial buffer */
1227         /* size generally less than 96k. Therefore we need to set the */
1228         /* maximum ssh window size to the maximum hpn buffer size */
1229         /* unless the user hasspecifically set the hpnrcvbufpoll */
1230         /* to no. In which case we *can* just set the window to the */
1231         /* minimum of the hpn buffer size and tcp receive buffer size */
1232
1233         if(options.hpn_disabled)
1234         {
1235                 options.hpn_buffer_size = CHAN_SES_WINDOW_DEFAULT;
1236         }
1237         else if (datafellows & SSH_BUG_LARGEWINDOW)
1238         {
1239                 debug("HPN to Non-HPN Connection");
1240                 if (options.hpn_buffer_size < 0)
1241                         options.hpn_buffer_size = 2*1024*1024;
1242         }
1243         else
1244         {
1245                 if (options.hpn_buffer_size < 0)
1246                         options.hpn_buffer_size = BUFFER_MAX_LEN_HPN;
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                 if (options.tcp_rcv_buf_poll <= 0)
1261                 {
1262                         options.hpn_buffer_size = MIN(socksize,options.hpn_buffer_size);
1263                         debug ("MIN of TCP RWIN and HPNBufferSize: %d", options.hpn_buffer_size);
1264                 }
1265                 else
1266                 {
1267                         if (options.tcp_rcv_buf > 0)
1268                                 options.hpn_buffer_size = MIN(options.tcp_rcv_buf, options.hpn_buffer_size);
1269                                 debug ("MIN of TCPRcvBuf and HPNBufferSize: %d", options.hpn_buffer_size);
1270                 }
1271
1272         }
1273
1274         debug("Final hpn_buffer_size = %d", options.hpn_buffer_size);
1275
1276         window = options.hpn_buffer_size;
1277
1278         packetmax = CHAN_SES_PACKET_DEFAULT;
1279         if (tty_flag) {
1280                 window = 4*CHAN_SES_PACKET_DEFAULT;
1281                 window >>= 1;
1282                 packetmax >>= 1;
1283         }
1284         c = channel_new(
1285             "session", SSH_CHANNEL_OPENING, in, out, err,
1286             window, packetmax, CHAN_EXTENDED_WRITE,
1287             "client-session", /*nonblock*/0);
1288         if ((options.tcp_rcv_buf_poll > 0) && (!options.hpn_disabled)) {
1289                 c->dynamic_window = 1;
1290                 debug ("Enabled Dynamic Window Scaling\n");
1291         }
1292         debug3("ssh_session2_open: channel_new: %d", c->self);
1293
1294         channel_send_open(c->self);
1295         if (!no_shell_flag)
1296                 channel_register_confirm(c->self, ssh_session2_setup, NULL);
1297
1298         return c->self;
1299 }
1300
1301 static int
1302 ssh_session2(void)
1303 {
1304         int id = -1;
1305
1306         /* XXX should be pre-session */
1307         ssh_init_forwarding();
1308         ssh_control_listener();
1309
1310         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1311                 id = ssh_session2_open();
1312
1313         /* Execute a local command */
1314         if (options.local_command != NULL &&
1315             options.permit_local_command)
1316                 ssh_local_cmd(options.local_command);
1317
1318         /* If requested, let ssh continue in the background. */
1319         if (fork_after_authentication_flag)
1320                 if (daemon(1, 1) < 0)
1321                         fatal("daemon() failed: %.200s", strerror(errno));
1322
1323         return client_loop(tty_flag, tty_flag ?
1324             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1325 }
1326
1327 static void
1328 load_public_identity_files(void)
1329 {
1330         char *filename, *cp, thishost[NI_MAXHOST];
1331         int i = 0;
1332         Key *public;
1333         struct passwd *pw;
1334 #ifdef SMARTCARD
1335         Key **keys;
1336
1337         if (options.smartcard_device != NULL &&
1338             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1339             (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL) {
1340                 int count = 0;
1341                 for (i = 0; keys[i] != NULL; i++) {
1342                         count++;
1343                         memmove(&options.identity_files[1], &options.identity_files[0],
1344                             sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1));
1345                         memmove(&options.identity_keys[1], &options.identity_keys[0],
1346                             sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1));
1347                         options.num_identity_files++;
1348                         options.identity_keys[0] = keys[i];
1349                         options.identity_files[0] = sc_get_key_label(keys[i]);
1350                 }
1351                 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES)
1352                         options.num_identity_files = SSH_MAX_IDENTITY_FILES;
1353                 i = count;
1354                 xfree(keys);
1355         }
1356 #endif /* SMARTCARD */
1357         if ((pw = getpwuid(original_real_uid)) == NULL)
1358                 fatal("load_public_identity_files: getpwuid failed");
1359         if (gethostname(thishost, sizeof(thishost)) == -1)
1360                 fatal("load_public_identity_files: gethostname: %s",
1361                     strerror(errno));
1362         for (; i < options.num_identity_files; i++) {
1363                 cp = tilde_expand_filename(options.identity_files[i],
1364                     original_real_uid);
1365                 filename = percent_expand(cp, "d", pw->pw_dir,
1366                     "u", pw->pw_name, "l", thishost, "h", host,
1367                     "r", options.user, (char *)NULL);
1368                 xfree(cp);
1369                 public = key_load_public(filename, NULL);
1370                 debug("identity file %s type %d", filename,
1371                     public ? public->type : -1);
1372                 xfree(options.identity_files[i]);
1373                 options.identity_files[i] = filename;
1374                 options.identity_keys[i] = public;
1375         }
1376 }
1377
1378 static void
1379 control_client_sighandler(int signo)
1380 {
1381         control_client_terminate = signo;
1382 }
1383
1384 static void
1385 control_client_sigrelay(int signo)
1386 {
1387         if (control_server_pid > 1)
1388                 kill(control_server_pid, signo);
1389 }
1390
1391 static int
1392 env_permitted(char *env)
1393 {
1394         int i, ret;
1395         char name[1024], *cp;
1396
1397         if ((cp = strchr(env, '=')) == NULL || cp == env)
1398                 return (0);
1399         ret = snprintf(name, sizeof(name), "%.*s", (int)(cp - env), env);
1400         if (ret <= 0 || (size_t)ret >= sizeof(name))
1401                 fatal("env_permitted: name '%.100s...' too long", env);
1402
1403         for (i = 0; i < options.num_send_env; i++)
1404                 if (match_pattern(name, options.send_env[i]))
1405                         return (1);
1406
1407         return (0);
1408 }
1409
1410 static void
1411 control_client(const char *path)
1412 {
1413         struct sockaddr_un addr;
1414         int i, r, fd, sock, exitval, num_env, addr_len;
1415         Buffer m;
1416         char *term;
1417         extern char **environ;
1418         u_int  flags;
1419
1420         if (mux_command == 0)
1421                 mux_command = SSHMUX_COMMAND_OPEN;
1422
1423         switch (options.control_master) {
1424         case SSHCTL_MASTER_AUTO:
1425         case SSHCTL_MASTER_AUTO_ASK:
1426                 debug("auto-mux: Trying existing master");
1427                 /* FALLTHROUGH */
1428         case SSHCTL_MASTER_NO:
1429                 break;
1430         default:
1431                 return;
1432         }
1433
1434         memset(&addr, '\0', sizeof(addr));
1435         addr.sun_family = AF_UNIX;
1436         addr_len = offsetof(struct sockaddr_un, sun_path) +
1437             strlen(path) + 1;
1438
1439         if (strlcpy(addr.sun_path, path,
1440             sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
1441                 fatal("ControlPath too long");
1442
1443         if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
1444                 fatal("%s socket(): %s", __func__, strerror(errno));
1445
1446         if (connect(sock, (struct sockaddr *)&addr, addr_len) == -1) {
1447                 if (mux_command != SSHMUX_COMMAND_OPEN) {
1448                         fatal("Control socket connect(%.100s): %s", path,
1449                             strerror(errno));
1450                 }
1451                 if (errno == ENOENT)
1452                         debug("Control socket \"%.100s\" does not exist", path);
1453                 else {
1454                         error("Control socket connect(%.100s): %s", path,
1455                             strerror(errno));
1456                 }
1457                 close(sock);
1458                 return;
1459         }
1460
1461         if (stdin_null_flag) {
1462                 if ((fd = open(_PATH_DEVNULL, O_RDONLY)) == -1)
1463                         fatal("open(/dev/null): %s", strerror(errno));
1464                 if (dup2(fd, STDIN_FILENO) == -1)
1465                         fatal("dup2: %s", strerror(errno));
1466                 if (fd > STDERR_FILENO)
1467                         close(fd);
1468         }
1469
1470         term = getenv("TERM");
1471
1472         flags = 0;
1473         if (tty_flag)
1474                 flags |= SSHMUX_FLAG_TTY;
1475         if (subsystem_flag)
1476                 flags |= SSHMUX_FLAG_SUBSYS;
1477         if (options.forward_x11)
1478                 flags |= SSHMUX_FLAG_X11_FWD;
1479         if (options.forward_agent)
1480                 flags |= SSHMUX_FLAG_AGENT_FWD;
1481         if (options.num_local_forwards > 0)
1482                 flags |= SSHMUX_FLAG_PORTFORWARD;
1483         buffer_init(&m);
1484
1485         /* Send our command to server */
1486         buffer_put_int(&m, mux_command);
1487         buffer_put_int(&m, flags);
1488         if (options.num_local_forwards > 0)
1489         {
1490                 if (options.local_forwards[0].listen_host == NULL)
1491                         buffer_put_string(&m,"LOCALHOST",11);
1492                 else
1493                         buffer_put_string(&m,options.local_forwards[0].listen_host,512);
1494                 buffer_put_int(&m,options.local_forwards[0].listen_port);
1495                 buffer_put_string(&m,options.local_forwards[0].connect_host,512);
1496                 buffer_put_int(&m,options.local_forwards[0].connect_port);
1497         }
1498         if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1)
1499                 fatal("%s: msg_send", __func__);
1500         buffer_clear(&m);
1501
1502         /* Get authorisation status and PID of controlee */
1503         if (ssh_msg_recv(sock, &m) == -1)
1504                 fatal("%s: msg_recv", __func__);
1505         if (buffer_get_char(&m) != SSHMUX_VER)
1506                 fatal("%s: wrong version", __func__);
1507         if (buffer_get_int(&m) != 1)
1508                 fatal("Connection to master denied");
1509         control_server_pid = buffer_get_int(&m);
1510
1511         buffer_clear(&m);
1512
1513         switch (mux_command) {
1514         case SSHMUX_COMMAND_ALIVE_CHECK:
1515                 fprintf(stderr, "Master running (pid=%d)\r\n",
1516                     control_server_pid);
1517                 exit(0);
1518         case SSHMUX_COMMAND_TERMINATE:
1519                 fprintf(stderr, "Exit request sent.\r\n");
1520                 exit(0);
1521         case SSHMUX_COMMAND_OPEN:
1522                 /* continue below */
1523                 break;
1524         default:
1525                 fatal("silly mux_command %d", mux_command);
1526         }
1527
1528         /* SSHMUX_COMMAND_OPEN */
1529         buffer_put_cstring(&m, term ? term : "");
1530         buffer_append(&command, "\0", 1);
1531         buffer_put_cstring(&m, buffer_ptr(&command));
1532
1533         if (options.num_send_env == 0 || environ == NULL) {
1534                 buffer_put_int(&m, 0);
1535         } else {
1536                 /* Pass environment */
1537                 num_env = 0;
1538                 for (i = 0; environ[i] != NULL; i++)
1539                         if (env_permitted(environ[i]))
1540                                 num_env++; /* Count */
1541
1542                 buffer_put_int(&m, num_env);
1543
1544                 for (i = 0; environ[i] != NULL && num_env >= 0; i++)
1545                         if (env_permitted(environ[i])) {
1546                                 num_env--;
1547                                 buffer_put_cstring(&m, environ[i]);
1548                         }
1549         }
1550
1551         if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1)
1552                 fatal("%s: msg_send", __func__);
1553
1554         mm_send_fd(sock, STDIN_FILENO);
1555         mm_send_fd(sock, STDOUT_FILENO);
1556         mm_send_fd(sock, STDERR_FILENO);
1557
1558         /* Wait for reply, so master has a chance to gather ttymodes */
1559         buffer_clear(&m);
1560         if (ssh_msg_recv(sock, &m) == -1)
1561                 fatal("%s: msg_recv", __func__);
1562         if (buffer_get_char(&m) != SSHMUX_VER)
1563                 fatal("%s: wrong version", __func__);
1564         buffer_free(&m);
1565
1566         signal(SIGHUP, control_client_sighandler);
1567         signal(SIGINT, control_client_sighandler);
1568         signal(SIGTERM, control_client_sighandler);
1569         signal(SIGWINCH, control_client_sigrelay);
1570
1571         if (tty_flag)
1572                 enter_raw_mode();
1573
1574         /* Stick around until the controlee closes the client_fd */
1575         exitval = 0;
1576         for (;!control_client_terminate;) {
1577                 r = read(sock, &exitval, sizeof(exitval));
1578                 if (r == 0) {
1579                         debug2("Received EOF from master");
1580                         break;
1581                 }
1582                 if (r > 0)
1583                         debug2("Received exit status from master %d", exitval);
1584                 if (r == -1 && errno != EINTR)
1585                         fatal("%s: read %s", __func__, strerror(errno));
1586         }
1587
1588         if (control_client_terminate)
1589                 debug2("Exiting on signal %d", control_client_terminate);
1590
1591         close(sock);
1592
1593         leave_raw_mode();
1594
1595         if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET)
1596                 fprintf(stderr, "Connection to master closed.\r\n");
1597
1598         exit(exitval);
1599 }