ssh.c

   1 /* $OpenBSD: ssh.c,v 1.293 2006/08/03 03:34:42 deraadt 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 <openssl/evp.h>
  71 #include <openssl/err.h>
  72
  73 #include "xmalloc.h"
  74 #include "ssh.h"
  75 #include "ssh1.h"
  76 #include "ssh2.h"
  77 #include "compat.h"
  78 #include "cipher.h"
  79 #include "packet.h"
  80 #include "buffer.h"
  81 #include "channels.h"
  82 #include "key.h"
  83 #include "authfd.h"
  84 #include "authfile.h"
  85 #include "pathnames.h"
  86 #include "dispatch.h"
  87 #include "clientloop.h"
  88 #include "log.h"
  89 #include "readconf.h"
  90 #include "sshconnect.h"
  91 #include "misc.h"
  92 #include "kex.h"
  93 #include "mac.h"
  94 #include "sshpty.h"
  95 #include "match.h"
  96 #include "msg.h"
  97 #include "monitor_fdpass.h"
  98 #include "uidswap.h"
  99 #include "version.h"
 100
 101 #ifdef SMARTCARD
 102 #include "scard.h"
 103 #endif
 104
 105 extern char *__progname;
 106
 107 /* Flag indicating whether debug mode is on.  This can be set on the command line. */
 108 int debug_flag = 0;
 109
 110 /* Flag indicating whether a tty should be allocated */
 111 int tty_flag = 0;
 112 int no_tty_flag = 0;
 113 int force_tty_flag = 0;
 114
 115 /* don't exec a shell */
 116 int no_shell_flag = 0;
 117
 118 /*
 119  * Flag indicating that nothing should be read from stdin.  This can be set
 120  * on the command line.
 121  */
 122 int stdin_null_flag = 0;
 123
 124 /*
 125  * Flag indicating that ssh should fork after authentication.  This is useful
 126  * so that the passphrase can be entered manually, and then ssh goes to the
 127  * background.
 128  */
 129 int fork_after_authentication_flag = 0;
 130
 131 /*
 132  * General data structure for command line options and options configurable
 133  * in configuration files.  See readconf.h.
 134  */
 135 Options options;
 136
 137 /* optional user configfile */
 138 char *config = NULL;
 139
 140 /*
 141  * Name of the host we are connecting to.  This is the name given on the
 142  * command line, or the HostName specified for the user-supplied name in a
 143  * configuration file.
 144  */
 145 char *host;
 146
 147 /* socket address the host resolves to */
 148 struct sockaddr_storage hostaddr;
 149
 150 /* Private host keys. */
 151 Sensitive sensitive_data;
 152
 153 /* Original real UID. */
 154 uid_t original_real_uid;
 155 uid_t original_effective_uid;
 156
 157 /* command to be executed */
 158 Buffer command;
 159
 160 /* Should we execute a command or invoke a subsystem? */
 161 int subsystem_flag = 0;
 162
 163 /* # of replies received for global requests */
 164 static int client_global_request_id = 0;
 165
 166 /* pid of proxycommand child process */
 167 pid_t proxy_command_pid = 0;
 168
 169 /* fd to control socket */
 170 int control_fd = -1;
 171
 172 /* Multiplexing control command */
 173 static u_int mux_command = 0;
 174
 175 /* Only used in control client mode */
 176 volatile sig_atomic_t control_client_terminate = 0;
 177 u_int control_server_pid = 0;
 178
 179 /* Prints a help message to the user.  This function never returns. */
 180
 181 static void
 182 usage(void)
 183 {
 184         fprintf(stderr,
 185 "usage: ssh [-1246AaCfgkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]\n"
 186 "           [-D [bind_address:]port] [-e escape_char] [-F configfile]\n"
 187 "           [-i identity_file] [-L [bind_address:]port:host:hostport]\n"
 188 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
 189 "           [-R [bind_address:]port:host:hostport] [-S ctl_path]\n"
 190 "           [-w local_tun[:remote_tun]] [user@]hostname [command]\n"
 191         );
 192         exit(255);
 193 }
 194
 195 static int ssh_session(void);
 196 static int ssh_session2(void);
 197 static void load_public_identity_files(void);
 198 static void control_client(const char *path);
 199
 200 /*
 201  * Main program for the ssh client.
 202  */
 203 int
 204 main(int ac, char **av)
 205 {
 206         int i, opt, exit_status;
 207         char *p, *cp, *line, buf[256];
 208         struct stat st;
 209         struct passwd *pw;
 210         int dummy;
 211         extern int optind, optreset;
 212         extern char *optarg;
 213         struct servent *sp;
 214         Forward fwd;
 215
 216         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 217         sanitise_stdfd();
 218
 219         __progname = ssh_get_progname(av[0]);
 220         init_rng();
 221
 222         /*
 223          * Save the original real uid.  It will be needed later (uid-swapping
 224          * may clobber the real uid).
 225          */
 226         original_real_uid = getuid();
 227         original_effective_uid = geteuid();
 228
 229         /*
 230          * Use uid-swapping to give up root privileges for the duration of
 231          * option processing.  We will re-instantiate the rights when we are
 232          * ready to create the privileged port, and will permanently drop
 233          * them when the port has been created (actually, when the connection
 234          * has been made, as we may need to create the port several times).
 235          */
 236         PRIV_END;
 237
 238 #ifdef HAVE_SETRLIMIT
 239         /* If we are installed setuid root be careful to not drop core. */
 240         if (original_real_uid != original_effective_uid) {
 241                 struct rlimit rlim;
 242                 rlim.rlim_cur = rlim.rlim_max = 0;
 243                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 244                         fatal("setrlimit failed: %.100s", strerror(errno));
 245         }
 246 #endif
 247         /* Get user data. */
 248         pw = getpwuid(original_real_uid);
 249         if (!pw) {
 250                 logit("You don't exist, go away!");
 251                 exit(255);
 252         }
 253         /* Take a copy of the returned structure. */
 254         pw = pwcopy(pw);
 255
 256         /*
 257          * Set our umask to something reasonable, as some files are created
 258          * with the default umask.  This will make them world-readable but
 259          * writable only by the owner, which is ok for all files for which we
 260          * don't set the modes explicitly.
 261          */
 262         umask(022);
 263
 264         /* Initialize option structure to indicate that no values have been set. */
 265         initialize_options(&options);
 266
 267         /* Parse command-line arguments. */
 268         host = NULL;
 269
 270  again:
 271         while ((opt = getopt(ac, av,
 272             "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:MNO:PR:S:TVw:XY")) != -1) {
 273                 switch (opt) {
 274                 case '1':
 275                         options.protocol = SSH_PROTO_1;
 276                         break;
 277                 case '2':
 278                         options.protocol = SSH_PROTO_2;
 279                         break;
 280                 case '4':
 281                         options.address_family = AF_INET;
 282                         break;
 283                 case '6':
 284                         options.address_family = AF_INET6;
 285                         break;
 286                 case 'n':
 287                         stdin_null_flag = 1;
 288                         break;
 289                 case 'f':
 290                         fork_after_authentication_flag = 1;
 291                         stdin_null_flag = 1;
 292                         break;
 293                 case 'x':
 294                         options.forward_x11 = 0;
 295                         break;
 296                 case 'X':
 297                         options.forward_x11 = 1;
 298                         break;
 299                 case 'Y':
 300                         options.forward_x11 = 1;
 301                         options.forward_x11_trusted = 1;
 302                         break;
 303                 case 'g':
 304                         options.gateway_ports = 1;
 305                         break;
 306                 case 'O':
 307                         if (strcmp(optarg, "check") == 0)
 308                                 mux_command = SSHMUX_COMMAND_ALIVE_CHECK;
 309                         else if (strcmp(optarg, "exit") == 0)
 310                                 mux_command = SSHMUX_COMMAND_TERMINATE;
 311                         else
 312                                 fatal("Invalid multiplex command.");
 313                         break;
 314                 case 'P':       /* deprecated */
 315                         options.use_privileged_port = 0;
 316                         break;
 317                 case 'a':
 318                         options.forward_agent = 0;
 319                         break;
 320                 case 'A':
 321                         options.forward_agent = 1;
 322                         break;
 323                 case 'k':
 324                         options.gss_deleg_creds = 0;
 325                         break;
 326                 case 'i':
 327                         if (stat(optarg, &st) < 0) {
 328                                 fprintf(stderr, "Warning: Identity file %s "
 329                                     "not accessible: %s.\n", optarg,
 330                                     strerror(errno));
 331                                 break;
 332                         }
 333                         if (options.num_identity_files >=
 334                             SSH_MAX_IDENTITY_FILES)
 335                                 fatal("Too many identity files specified "
 336                                     "(max %d)", SSH_MAX_IDENTITY_FILES);
 337                         options.identity_files[options.num_identity_files++] =
 338                             xstrdup(optarg);
 339                         break;
 340                 case 'I':
 341 #ifdef SMARTCARD
 342                         options.smartcard_device = xstrdup(optarg);
 343 #else
 344                         fprintf(stderr, "no support for smartcards.\n");
 345 #endif
 346                         break;
 347                 case 't':
 348                         if (tty_flag)
 349                                 force_tty_flag = 1;
 350                         tty_flag = 1;
 351                         break;
 352                 case 'v':
 353                         if (debug_flag == 0) {
 354                                 debug_flag = 1;
 355                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 356                         } else {
 357                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
 358                                         options.log_level++;
 359                                 break;
 360                         }
 361                         /* FALLTHROUGH */
 362                 case 'V':
 363                         fprintf(stderr, "%s, %s\n",
 364                             SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
 365                         if (opt == 'V')
 366                                 exit(0);
 367                         break;
 368                 case 'w':
 369                         if (options.tun_open == -1)
 370                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 371                         options.tun_local = a2tun(optarg, &options.tun_remote);
 372                         if (options.tun_local == SSH_TUNID_ERR) {
 373                                 fprintf(stderr, "Bad tun device '%s'\n", optarg);
 374                                 exit(255);
 375                         }
 376                         break;
 377                 case 'q':
 378                         options.log_level = SYSLOG_LEVEL_QUIET;
 379                         break;
 380                 case 'e':
 381                         if (optarg[0] == '^' && optarg[2] == 0 &&
 382                             (u_char) optarg[1] >= 64 &&
 383                             (u_char) optarg[1] < 128)
 384                                 options.escape_char = (u_char) optarg[1] & 31;
 385                         else if (strlen(optarg) == 1)
 386                                 options.escape_char = (u_char) optarg[0];
 387                         else if (strcmp(optarg, "none") == 0)
 388                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 389                         else {
 390                                 fprintf(stderr, "Bad escape character '%s'.\n",
 391                                     optarg);
 392                                 exit(255);
 393                         }
 394                         break;
 395                 case 'c':
 396                         if (ciphers_valid(optarg)) {
 397                                 /* SSH2 only */
 398                                 options.ciphers = xstrdup(optarg);
 399                                 options.cipher = SSH_CIPHER_INVALID;
 400                         } else {
 401                                 /* SSH1 only */
 402                                 options.cipher = cipher_number(optarg);
 403                                 if (options.cipher == -1) {
 404                                         fprintf(stderr,
 405                                             "Unknown cipher type '%s'\n",
 406                                             optarg);
 407                                         exit(255);
 408                                 }
 409                                 if (options.cipher == SSH_CIPHER_3DES)
 410                                         options.ciphers = "3des-cbc";
 411                                 else if (options.cipher == SSH_CIPHER_BLOWFISH)
 412                                         options.ciphers = "blowfish-cbc";
 413                                 else
 414                                         options.ciphers = (char *)-1;
 415                         }
 416                         break;
 417                 case 'm':
 418                         if (mac_valid(optarg))
 419                                 options.macs = xstrdup(optarg);
 420                         else {
 421                                 fprintf(stderr, "Unknown mac type '%s'\n",
 422                                     optarg);
 423                                 exit(255);
 424                         }
 425                         break;
 426                 case 'M':
 427                         if (options.control_master == SSHCTL_MASTER_YES)
 428                                 options.control_master = SSHCTL_MASTER_ASK;
 429                         else
 430                                 options.control_master = SSHCTL_MASTER_YES;
 431                         break;
 432                 case 'p':
 433                         options.port = a2port(optarg);
 434                         if (options.port == 0) {
 435                                 fprintf(stderr, "Bad port '%s'\n", optarg);
 436                                 exit(255);
 437                         }
 438                         break;
 439                 case 'l':
 440                         options.user = optarg;
 441                         break;
 442
 443                 case 'L':
 444                         if (parse_forward(&fwd, optarg))
 445                                 add_local_forward(&options, &fwd);
 446                         else {
 447                                 fprintf(stderr,
 448                                     "Bad local forwarding specification '%s'\n",
 449                                     optarg);
 450                                 exit(255);
 451                         }
 452                         break;
 453
 454                 case 'R':
 455                         if (parse_forward(&fwd, optarg)) {
 456                                 add_remote_forward(&options, &fwd);
 457                         } else {
 458                                 fprintf(stderr,
 459                                     "Bad remote forwarding specification "
 460                                     "'%s'\n", optarg);
 461                                 exit(255);
 462                         }
 463                         break;
 464
 465                 case 'D':
 466                         cp = p = xstrdup(optarg);
 467                         memset(&fwd, '\0', sizeof(fwd));
 468                         fwd.connect_host = "socks";
 469                         if ((fwd.listen_host = hpdelim(&cp)) == NULL) {
 470                                 fprintf(stderr, "Bad dynamic forwarding "
 471                                     "specification '%.100s'\n", optarg);
 472                                 exit(255);
 473                         }
 474                         if (cp != NULL) {
 475                                 fwd.listen_port = a2port(cp);
 476                                 fwd.listen_host = cleanhostname(fwd.listen_host);
 477                         } else {
 478                                 fwd.listen_port = a2port(fwd.listen_host);
 479                                 fwd.listen_host = NULL;
 480                         }
 481
 482                         if (fwd.listen_port == 0) {
 483                                 fprintf(stderr, "Bad dynamic port '%s'\n",
 484                                     optarg);
 485                                 exit(255);
 486                         }
 487                         add_local_forward(&options, &fwd);
 488                         xfree(p);
 489                         break;
 490
 491                 case 'C':
 492                         options.compression = 1;
 493                         break;
 494                 case 'N':
 495                         no_shell_flag = 1;
 496                         no_tty_flag = 1;
 497                         break;
 498                 case 'T':
 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 's':
 510                         subsystem_flag = 1;
 511                         break;
 512                 case 'S':
 513                         if (options.control_path != NULL)
 514                                 free(options.control_path);
 515                         options.control_path = xstrdup(optarg);
 516                         break;
 517                 case 'b':
 518                         options.bind_address = optarg;
 519                         break;
 520                 case 'F':
 521                         config = optarg;
 522                         break;
 523                 default:
 524                         usage();
 525                 }
 526         }
 527
 528         ac -= optind;
 529         av += optind;
 530
 531         if (ac > 0 && !host && **av != '-') {
 532                 if (strrchr(*av, '@')) {
 533                         p = xstrdup(*av);
 534                         cp = strrchr(p, '@');
 535                         if (cp == NULL || cp == p)
 536                                 usage();
 537                         options.user = p;
 538                         *cp = '\0';
 539                         host = ++cp;
 540                 } else
 541                         host = *av;
 542                 if (ac > 1) {
 543                         optind = optreset = 1;
 544                         goto again;
 545                 }
 546                 ac--, av++;
 547         }
 548
 549         /* Check that we got a host name. */
 550         if (!host)
 551                 usage();
 552
 553         SSLeay_add_all_algorithms();
 554         ERR_load_crypto_strings();
 555
 556         /* Initialize the command to execute on remote host. */
 557         buffer_init(&command);
 558
 559         /*
 560          * Save the command to execute on the remote host in a buffer. There
 561          * is no limit on the length of the command, except by the maximum
 562          * packet size.  Also sets the tty flag if there is no command.
 563          */
 564         if (!ac) {
 565                 /* No command specified - execute shell on a tty. */
 566                 tty_flag = 1;
 567                 if (subsystem_flag) {
 568                         fprintf(stderr,
 569                             "You must specify a subsystem to invoke.\n");
 570                         usage();
 571                 }
 572         } else {
 573                 /* A command has been specified.  Store it into the buffer. */
 574                 for (i = 0; i < ac; i++) {
 575                         if (i)
 576                                 buffer_append(&command, " ", 1);
 577                         buffer_append(&command, av[i], strlen(av[i]));
 578                 }
 579         }
 580
 581         /* Cannot fork to background if no command. */
 582         if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag)
 583                 fatal("Cannot fork into background without a command to execute.");
 584
 585         /* Allocate a tty by default if no command specified. */
 586         if (buffer_len(&command) == 0)
 587                 tty_flag = 1;
 588
 589         /* Force no tty */
 590         if (no_tty_flag)
 591                 tty_flag = 0;
 592         /* Do not allocate a tty if stdin is not a tty. */
 593         if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) {
 594                 if (tty_flag)
 595                         logit("Pseudo-terminal will not be allocated because stdin is not a terminal.");
 596                 tty_flag = 0;
 597         }
 598
 599         /*
 600          * Initialize "log" output.  Since we are the client all output
 601          * actually goes to stderr.
 602          */
 603         log_init(av[0], options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
 604             SYSLOG_FACILITY_USER, 1);
 605
 606         /*
 607          * Read per-user configuration file.  Ignore the system wide config
 608          * file if the user specifies a config file on the command line.
 609          */
 610         if (config != NULL) {
 611                 if (!read_config_file(config, host, &options, 0))
 612                         fatal("Can't open user config file %.100s: "
 613                             "%.100s", config, strerror(errno));
 614         } else  {
 615                 snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir,
 616                     _PATH_SSH_USER_CONFFILE);
 617                 (void)read_config_file(buf, host, &options, 1);
 618
 619                 /* Read systemwide configuration file after use config. */
 620                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host,
 621                     &options, 0);
 622         }
 623
 624         /* Fill configuration defaults. */
 625         fill_default_options(&options);
 626
 627         channel_set_af(options.address_family);
 628
 629         /* reinit */
 630         log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1);
 631
 632         seed_rng();
 633
 634         if (options.user == NULL)
 635                 options.user = xstrdup(pw->pw_name);
 636
 637         if (options.hostname != NULL)
 638                 host = options.hostname;
 639
 640         /* force lowercase for hostkey matching */
 641         if (options.host_key_alias != NULL) {
 642                 for (p = options.host_key_alias; *p; p++)
 643                         if (isupper(*p))
 644                                 *p = (char)tolower(*p);
 645         }
 646
 647         /* Get default port if port has not been set. */
 648         if (options.port == 0) {
 649                 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
 650                 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT;
 651         }
 652
 653         if (options.proxy_command != NULL &&
 654             strcmp(options.proxy_command, "none") == 0)
 655                 options.proxy_command = NULL;
 656         if (options.control_path != NULL &&
 657             strcmp(options.control_path, "none") == 0)
 658                 options.control_path = NULL;
 659
 660         if (options.control_path != NULL) {
 661                 char thishost[NI_MAXHOST];
 662
 663                 if (gethostname(thishost, sizeof(thishost)) == -1)
 664                         fatal("gethostname: %s", strerror(errno));
 665                 snprintf(buf, sizeof(buf), "%d", options.port);
 666                 cp = tilde_expand_filename(options.control_path,
 667                     original_real_uid);
 668                 options.control_path = percent_expand(cp, "p", buf, "h", host,
 669                     "r", options.user, "l", thishost, (char *)NULL);
 670                 xfree(cp);
 671         }
 672         if (mux_command != 0 && options.control_path == NULL)
 673                 fatal("No ControlPath specified for \"-O\" command");
 674         if (options.control_path != NULL)
 675                 control_client(options.control_path);
 676
 677         /* Open a connection to the remote host. */
 678         if (ssh_connect(host, &hostaddr, options.port,
 679             options.address_family, options.connection_attempts,
 680 #ifdef HAVE_CYGWIN
 681             options.use_privileged_port,
 682 #else
 683             original_effective_uid == 0 && options.use_privileged_port,
 684 #endif
 685             options.proxy_command) != 0)
 686                 exit(255);
 687
 688         /*
 689          * If we successfully made the connection, load the host private key
 690          * in case we will need it later for combined rsa-rhosts
 691          * authentication. This must be done before releasing extra
 692          * privileges, because the file is only readable by root.
 693          * If we cannot access the private keys, load the public keys
 694          * instead and try to execute the ssh-keysign helper instead.
 695          */
 696         sensitive_data.nkeys = 0;
 697         sensitive_data.keys = NULL;
 698         sensitive_data.external_keysign = 0;
 699         if (options.rhosts_rsa_authentication ||
 700             options.hostbased_authentication) {
 701                 sensitive_data.nkeys = 3;
 702                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
 703                     sizeof(Key));
 704
 705                 PRIV_START;
 706                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
 707                     _PATH_HOST_KEY_FILE, "", NULL, NULL);
 708                 sensitive_data.keys[1] = key_load_private_type(KEY_DSA,
 709                     _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
 710                 sensitive_data.keys[2] = key_load_private_type(KEY_RSA,
 711                     _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
 712                 PRIV_END;
 713
 714                 if (options.hostbased_authentication == 1 &&
 715                     sensitive_data.keys[0] == NULL &&
 716                     sensitive_data.keys[1] == NULL &&
 717                     sensitive_data.keys[2] == NULL) {
 718                         sensitive_data.keys[1] = key_load_public(
 719                             _PATH_HOST_DSA_KEY_FILE, NULL);
 720                         sensitive_data.keys[2] = key_load_public(
 721                             _PATH_HOST_RSA_KEY_FILE, NULL);
 722                         sensitive_data.external_keysign = 1;
 723                 }
 724         }
 725         /*
 726          * Get rid of any extra privileges that we may have.  We will no
 727          * longer need them.  Also, extra privileges could make it very hard
 728          * to read identity files and other non-world-readable files from the
 729          * user's home directory if it happens to be on a NFS volume where
 730          * root is mapped to nobody.
 731          */
 732         if (original_effective_uid == 0) {
 733                 PRIV_START;
 734                 permanently_set_uid(pw);
 735         }
 736
 737         /*
 738          * Now that we are back to our own permissions, create ~/.ssh
 739          * directory if it doesn't already exist.
 740          */
 741         snprintf(buf, sizeof buf, "%.100s%s%.100s", pw->pw_dir, strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
 742         if (stat(buf, &st) < 0)
 743                 if (mkdir(buf, 0700) < 0)
 744                         error("Could not create directory '%.200s'.", buf);
 745
 746         /* load options.identity_files */
 747         load_public_identity_files();
 748
 749         /* Expand ~ in known host file names. */
 750         /* XXX mem-leaks: */
 751         options.system_hostfile =
 752             tilde_expand_filename(options.system_hostfile, original_real_uid);
 753         options.user_hostfile =
 754             tilde_expand_filename(options.user_hostfile, original_real_uid);
 755         options.system_hostfile2 =
 756             tilde_expand_filename(options.system_hostfile2, original_real_uid);
 757         options.user_hostfile2 =
 758             tilde_expand_filename(options.user_hostfile2, original_real_uid);
 759
 760         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
 761
 762         /* Log into the remote system.  This never returns if the login fails. */
 763         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, pw);
 764
 765         /* We no longer need the private host keys.  Clear them now. */
 766         if (sensitive_data.nkeys != 0) {
 767                 for (i = 0; i < sensitive_data.nkeys; i++) {
 768                         if (sensitive_data.keys[i] != NULL) {
 769                                 /* Destroys contents safely */
 770                                 debug3("clear hostkey %d", i);
 771                                 key_free(sensitive_data.keys[i]);
 772                                 sensitive_data.keys[i] = NULL;
 773                         }
 774                 }
 775                 xfree(sensitive_data.keys);
 776         }
 777         for (i = 0; i < options.num_identity_files; i++) {
 778                 if (options.identity_files[i]) {
 779                         xfree(options.identity_files[i]);
 780                         options.identity_files[i] = NULL;
 781                 }
 782                 if (options.identity_keys[i]) {
 783                         key_free(options.identity_keys[i]);
 784                         options.identity_keys[i] = NULL;
 785                 }
 786         }
 787
 788         exit_status = compat20 ? ssh_session2() : ssh_session();
 789         packet_close();
 790
 791         if (options.control_path != NULL && control_fd != -1)
 792                 unlink(options.control_path);
 793
 794         /*
 795          * Send SIGHUP to proxy command if used. We don't wait() in
 796          * case it hangs and instead rely on init to reap the child
 797          */
 798         if (proxy_command_pid > 1)
 799                 kill(proxy_command_pid, SIGHUP);
 800
 801         return exit_status;
 802 }
 803
 804 static void
 805 ssh_init_forwarding(void)
 806 {
 807         int success = 0;
 808         int i;
 809
 810         /* Initiate local TCP/IP port forwardings. */
 811         for (i = 0; i < options.num_local_forwards; i++) {
 812                 debug("Local connections to %.200s:%d forwarded to remote "
 813                     "address %.200s:%d",
 814                     (options.local_forwards[i].listen_host == NULL) ?
 815                     (options.gateway_ports ? "*" : "LOCALHOST") :
 816                     options.local_forwards[i].listen_host,
 817                     options.local_forwards[i].listen_port,
 818                     options.local_forwards[i].connect_host,
 819                     options.local_forwards[i].connect_port);
 820                 success += channel_setup_local_fwd_listener(
 821                     options.local_forwards[i].listen_host,
 822                     options.local_forwards[i].listen_port,
 823                     options.local_forwards[i].connect_host,
 824                     options.local_forwards[i].connect_port,
 825                     options.gateway_ports);
 826         }
 827         if (i > 0 && success != i && options.exit_on_forward_failure)
 828                 fatal("Could not request local forwarding.");
 829         if (i > 0 && success == 0)
 830                 error("Could not request local forwarding.");
 831
 832         /* Initiate remote TCP/IP port forwardings. */
 833         for (i = 0; i < options.num_remote_forwards; i++) {
 834                 debug("Remote connections from %.200s:%d forwarded to "
 835                     "local address %.200s:%d",
 836                     (options.remote_forwards[i].listen_host == NULL) ?
 837                     "LOCALHOST" : options.remote_forwards[i].listen_host,
 838                     options.remote_forwards[i].listen_port,
 839                     options.remote_forwards[i].connect_host,
 840                     options.remote_forwards[i].connect_port);
 841                 if (channel_request_remote_forwarding(
 842                     options.remote_forwards[i].listen_host,
 843                     options.remote_forwards[i].listen_port,
 844                     options.remote_forwards[i].connect_host,
 845                     options.remote_forwards[i].connect_port) < 0) {
 846                         if (options.exit_on_forward_failure)
 847                                 fatal("Could not request remote forwarding.");
 848                         else
 849                                 logit("Warning: Could not request remote "
 850                                     "forwarding.");
 851                 }
 852         }
 853 }
 854
 855 static void
 856 check_agent_present(void)
 857 {
 858         if (options.forward_agent) {
 859                 /* Clear agent forwarding if we don't have an agent. */
 860                 if (!ssh_agent_present())
 861                         options.forward_agent = 0;
 862         }
 863 }
 864
 865 static int
 866 ssh_session(void)
 867 {
 868         int type;
 869         int interactive = 0;
 870         int have_tty = 0;
 871         struct winsize ws;
 872         char *cp;
 873         const char *display;
 874
 875         /* Enable compression if requested. */
 876         if (options.compression) {
 877                 debug("Requesting compression at level %d.", options.compression_level);
 878
 879                 if (options.compression_level < 1 || options.compression_level > 9)
 880                         fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
 881
 882                 /* Send the request. */
 883                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
 884                 packet_put_int(options.compression_level);
 885                 packet_send();
 886                 packet_write_wait();
 887                 type = packet_read();
 888                 if (type == SSH_SMSG_SUCCESS)
 889                         packet_start_compression(options.compression_level);
 890                 else if (type == SSH_SMSG_FAILURE)
 891                         logit("Warning: Remote host refused compression.");
 892                 else
 893                         packet_disconnect("Protocol error waiting for compression response.");
 894         }
 895         /* Allocate a pseudo tty if appropriate. */
 896         if (tty_flag) {
 897                 debug("Requesting pty.");
 898
 899                 /* Start the packet. */
 900                 packet_start(SSH_CMSG_REQUEST_PTY);
 901
 902                 /* Store TERM in the packet.  There is no limit on the
 903                    length of the string. */
 904                 cp = getenv("TERM");
 905                 if (!cp)
 906                         cp = "";
 907                 packet_put_cstring(cp);
 908
 909                 /* Store window size in the packet. */
 910                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
 911                         memset(&ws, 0, sizeof(ws));
 912                 packet_put_int((u_int)ws.ws_row);
 913                 packet_put_int((u_int)ws.ws_col);
 914                 packet_put_int((u_int)ws.ws_xpixel);
 915                 packet_put_int((u_int)ws.ws_ypixel);
 916
 917                 /* Store tty modes in the packet. */
 918                 tty_make_modes(fileno(stdin), NULL);
 919
 920                 /* Send the packet, and wait for it to leave. */
 921                 packet_send();
 922                 packet_write_wait();
 923
 924                 /* Read response from the server. */
 925                 type = packet_read();
 926                 if (type == SSH_SMSG_SUCCESS) {
 927                         interactive = 1;
 928                         have_tty = 1;
 929                 } else if (type == SSH_SMSG_FAILURE)
 930                         logit("Warning: Remote host failed or refused to allocate a pseudo tty.");
 931                 else
 932                         packet_disconnect("Protocol error waiting for pty request response.");
 933         }
 934         /* Request X11 forwarding if enabled and DISPLAY is set. */
 935         display = getenv("DISPLAY");
 936         if (options.forward_x11 && display != NULL) {
 937                 char *proto, *data;
 938                 /* Get reasonable local authentication information. */
 939                 client_x11_get_proto(display, options.xauth_location,
 940                     options.forward_x11_trusted, &proto, &data);
 941                 /* Request forwarding with authentication spoofing. */
 942                 debug("Requesting X11 forwarding with authentication spoofing.");
 943                 x11_request_forwarding_with_spoofing(0, display, proto, data);
 944
 945                 /* Read response from the server. */
 946                 type = packet_read();
 947                 if (type == SSH_SMSG_SUCCESS) {
 948                         interactive = 1;
 949                 } else if (type == SSH_SMSG_FAILURE) {
 950                         logit("Warning: Remote host denied X11 forwarding.");
 951                 } else {
 952                         packet_disconnect("Protocol error waiting for X11 forwarding");
 953                 }
 954         }
 955         /* Tell the packet module whether this is an interactive session. */
 956         packet_set_interactive(interactive);
 957
 958         /* Request authentication agent forwarding if appropriate. */
 959         check_agent_present();
 960
 961         if (options.forward_agent) {
 962                 debug("Requesting authentication agent forwarding.");
 963                 auth_request_forwarding();
 964
 965                 /* Read response from the server. */
 966                 type = packet_read();
 967                 packet_check_eom();
 968                 if (type != SSH_SMSG_SUCCESS)
 969                         logit("Warning: Remote host denied authentication agent forwarding.");
 970         }
 971
 972         /* Initiate port forwardings. */
 973         ssh_init_forwarding();
 974
 975         /* If requested, let ssh continue in the background. */
 976         if (fork_after_authentication_flag)
 977                 if (daemon(1, 1) < 0)
 978                         fatal("daemon() failed: %.200s", strerror(errno));
 979
 980         /*
 981          * If a command was specified on the command line, execute the
 982          * command now. Otherwise request the server to start a shell.
 983          */
 984         if (buffer_len(&command) > 0) {
 985                 int len = buffer_len(&command);
 986                 if (len > 900)
 987                         len = 900;
 988                 debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command));
 989                 packet_start(SSH_CMSG_EXEC_CMD);
 990                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
 991                 packet_send();
 992                 packet_write_wait();
 993         } else {
 994                 debug("Requesting shell.");
 995                 packet_start(SSH_CMSG_EXEC_SHELL);
 996                 packet_send();
 997                 packet_write_wait();
 998         }
 999
1000         /* Enter the interactive session. */
1001         return client_loop(have_tty, tty_flag ?
1002             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1003 }
1004
1005 static void
1006 ssh_subsystem_reply(int type, u_int32_t seq, void *ctxt)
1007 {
1008         int id, len;
1009
1010         id = packet_get_int();
1011         len = buffer_len(&command);
1012         if (len > 900)
1013                 len = 900;
1014         packet_check_eom();
1015         if (type == SSH2_MSG_CHANNEL_FAILURE)
1016                 fatal("Request for subsystem '%.*s' failed on channel %d",
1017                     len, (u_char *)buffer_ptr(&command), id);
1018 }
1019
1020 void
1021 client_global_request_reply_fwd(int type, u_int32_t seq, void *ctxt)
1022 {
1023         int i;
1024
1025         i = client_global_request_id++;
1026         if (i >= options.num_remote_forwards)
1027                 return;
1028         debug("remote forward %s for: listen %d, connect %s:%d",
1029             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1030             options.remote_forwards[i].listen_port,
1031             options.remote_forwards[i].connect_host,
1032             options.remote_forwards[i].connect_port);
1033         if (type == SSH2_MSG_REQUEST_FAILURE) {
1034                 if (options.exit_on_forward_failure)
1035                         fatal("Error: remote port forwarding failed for "
1036                             "listen port %d",
1037                             options.remote_forwards[i].listen_port);
1038                 else
1039                         logit("Warning: remote port forwarding failed for "
1040                             "listen port %d",
1041                             options.remote_forwards[i].listen_port);
1042         }
1043 }
1044
1045 static void
1046 ssh_control_listener(void)
1047 {
1048         struct sockaddr_un addr;
1049         mode_t old_umask;
1050         int addr_len;
1051
1052         if (options.control_path == NULL ||
1053             options.control_master == SSHCTL_MASTER_NO)
1054                 return;
1055
1056         debug("setting up multiplex master socket");
1057
1058         memset(&addr, '\0', sizeof(addr));
1059         addr.sun_family = AF_UNIX;
1060         addr_len = offsetof(struct sockaddr_un, sun_path) +
1061             strlen(options.control_path) + 1;
1062
1063         if (strlcpy(addr.sun_path, options.control_path,
1064             sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
1065                 fatal("ControlPath too long");
1066
1067         if ((control_fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
1068                 fatal("%s socket(): %s", __func__, strerror(errno));
1069
1070         old_umask = umask(0177);
1071         if (bind(control_fd, (struct sockaddr *)&addr, addr_len) == -1) {
1072                 control_fd = -1;
1073                 if (errno == EINVAL || errno == EADDRINUSE)
1074                         fatal("ControlSocket %s already exists",
1075                             options.control_path);
1076                 else
1077                         fatal("%s bind(): %s", __func__, strerror(errno));
1078         }
1079         umask(old_umask);
1080
1081         if (listen(control_fd, 64) == -1)
1082                 fatal("%s listen(): %s", __func__, strerror(errno));
1083
1084         set_nonblock(control_fd);
1085 }
1086
1087 /* request pty/x11/agent/tcpfwd/shell for channel */
1088 static void
1089 ssh_session2_setup(int id, void *arg)
1090 {
1091         extern char **environ;
1092         const char *display;
1093         int interactive = tty_flag;
1094
1095         display = getenv("DISPLAY");
1096         if (options.forward_x11 && display != NULL) {
1097                 char *proto, *data;
1098                 /* Get reasonable local authentication information. */
1099                 client_x11_get_proto(display, options.xauth_location,
1100                     options.forward_x11_trusted, &proto, &data);
1101                 /* Request forwarding with authentication spoofing. */
1102                 debug("Requesting X11 forwarding with authentication spoofing.");
1103                 x11_request_forwarding_with_spoofing(id, display, proto, data);
1104                 interactive = 1;
1105                 /* XXX wait for reply */
1106         }
1107
1108         check_agent_present();
1109         if (options.forward_agent) {
1110                 debug("Requesting authentication agent forwarding.");
1111                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1112                 packet_send();
1113         }
1114
1115         if (options.tun_open != SSH_TUNMODE_NO) {
1116                 Channel *c;
1117                 int fd;
1118
1119                 debug("Requesting tun.");
1120                 if ((fd = tun_open(options.tun_local,
1121                     options.tun_open)) >= 0) {
1122                         c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1,
1123                             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1124                             0, "tun", 1);
1125                         c->datagram = 1;
1126 #if defined(SSH_TUN_FILTER)
1127                         if (options.tun_open == SSH_TUNMODE_POINTOPOINT)
1128                                 channel_register_filter(c->self, sys_tun_infilter,
1129                                     sys_tun_outfilter);
1130 #endif
1131                         packet_start(SSH2_MSG_CHANNEL_OPEN);
1132                         packet_put_cstring("tun@openssh.com");
1133                         packet_put_int(c->self);
1134                         packet_put_int(c->local_window_max);
1135                         packet_put_int(c->local_maxpacket);
1136                         packet_put_int(options.tun_open);
1137                         packet_put_int(options.tun_remote);
1138                         packet_send();
1139                 }
1140         }
1141
1142         client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1143             NULL, fileno(stdin), &command, environ, &ssh_subsystem_reply);
1144
1145         packet_set_interactive(interactive);
1146 }
1147
1148 /* open new channel for a session */
1149 static int
1150 ssh_session2_open(void)
1151 {
1152         Channel *c;
1153         int window, packetmax, in, out, err;
1154
1155         if (stdin_null_flag) {
1156                 in = open(_PATH_DEVNULL, O_RDONLY);
1157         } else {
1158                 in = dup(STDIN_FILENO);
1159         }
1160         out = dup(STDOUT_FILENO);
1161         err = dup(STDERR_FILENO);
1162
1163         if (in < 0 || out < 0 || err < 0)
1164                 fatal("dup() in/out/err failed");
1165
1166         /* enable nonblocking unless tty */
1167         if (!isatty(in))
1168                 set_nonblock(in);
1169         if (!isatty(out))
1170                 set_nonblock(out);
1171         if (!isatty(err))
1172                 set_nonblock(err);
1173
1174         window = CHAN_SES_WINDOW_DEFAULT;
1175         packetmax = CHAN_SES_PACKET_DEFAULT;
1176         if (tty_flag) {
1177                 window >>= 1;
1178                 packetmax >>= 1;
1179         }
1180         c = channel_new(
1181             "session", SSH_CHANNEL_OPENING, in, out, err,
1182             window, packetmax, CHAN_EXTENDED_WRITE,
1183             "client-session", /*nonblock*/0);
1184
1185         debug3("ssh_session2_open: channel_new: %d", c->self);
1186
1187         channel_send_open(c->self);
1188         if (!no_shell_flag)
1189                 channel_register_confirm(c->self, ssh_session2_setup, NULL);
1190
1191         return c->self;
1192 }
1193
1194 static int
1195 ssh_session2(void)
1196 {
1197         int id = -1;
1198
1199         /* XXX should be pre-session */
1200         ssh_init_forwarding();
1201         ssh_control_listener();
1202
1203         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1204                 id = ssh_session2_open();
1205
1206         /* Execute a local command */
1207         if (options.local_command != NULL &&
1208             options.permit_local_command)
1209                 ssh_local_cmd(options.local_command);
1210
1211         /* If requested, let ssh continue in the background. */
1212         if (fork_after_authentication_flag)
1213                 if (daemon(1, 1) < 0)
1214                         fatal("daemon() failed: %.200s", strerror(errno));
1215
1216         return client_loop(tty_flag, tty_flag ?
1217             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1218 }
1219
1220 static void
1221 load_public_identity_files(void)
1222 {
1223         char *filename, *cp, thishost[NI_MAXHOST];
1224         int i = 0;
1225         Key *public;
1226         struct passwd *pw;
1227 #ifdef SMARTCARD
1228         Key **keys;
1229
1230         if (options.smartcard_device != NULL &&
1231             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1232             (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL) {
1233                 int count = 0;
1234                 for (i = 0; keys[i] != NULL; i++) {
1235                         count++;
1236                         memmove(&options.identity_files[1], &options.identity_files[0],
1237                             sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1));
1238                         memmove(&options.identity_keys[1], &options.identity_keys[0],
1239                             sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1));
1240                         options.num_identity_files++;
1241                         options.identity_keys[0] = keys[i];
1242                         options.identity_files[0] = sc_get_key_label(keys[i]);
1243                 }
1244                 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES)
1245                         options.num_identity_files = SSH_MAX_IDENTITY_FILES;
1246                 i = count;
1247                 xfree(keys);
1248         }
1249 #endif /* SMARTCARD */
1250         if ((pw = getpwuid(original_real_uid)) == NULL)
1251                 fatal("load_public_identity_files: getpwuid failed");
1252         if (gethostname(thishost, sizeof(thishost)) == -1)
1253                 fatal("load_public_identity_files: gethostname: %s",
1254                     strerror(errno));
1255         for (; i < options.num_identity_files; i++) {
1256                 cp = tilde_expand_filename(options.identity_files[i],
1257                     original_real_uid);
1258                 filename = percent_expand(cp, "d", pw->pw_dir,
1259                     "u", pw->pw_name, "l", thishost, "h", host,
1260                     "r", options.user, (char *)NULL);
1261                 xfree(cp);
1262                 public = key_load_public(filename, NULL);
1263                 debug("identity file %s type %d", filename,
1264                     public ? public->type : -1);
1265                 xfree(options.identity_files[i]);
1266                 options.identity_files[i] = filename;
1267                 options.identity_keys[i] = public;
1268         }
1269 }
1270
1271 static void
1272 control_client_sighandler(int signo)
1273 {
1274         control_client_terminate = signo;
1275 }
1276
1277 static void
1278 control_client_sigrelay(int signo)
1279 {
1280         if (control_server_pid > 1)
1281                 kill(control_server_pid, signo);
1282 }
1283
1284 static int
1285 env_permitted(char *env)
1286 {
1287         int i, ret;
1288         char name[1024], *cp;
1289
1290         if ((cp = strchr(env, '=')) == NULL || cp == env)
1291                 return (0);
1292         ret = snprintf(name, sizeof(name), "%.*s", (int)(cp - env), env);
1293         if (ret <= 0 || (size_t)ret >= sizeof(name))
1294                 fatal("env_permitted: name '%.100s...' too long", env);
1295
1296         for (i = 0; i < options.num_send_env; i++)
1297                 if (match_pattern(name, options.send_env[i]))
1298                         return (1);
1299
1300         return (0);
1301 }
1302
1303 static void
1304 control_client(const char *path)
1305 {
1306         struct sockaddr_un addr;
1307         int i, r, fd, sock, exitval, num_env, addr_len;
1308         Buffer m;
1309         char *term;
1310         extern char **environ;
1311         u_int  flags;
1312
1313         if (mux_command == 0)
1314                 mux_command = SSHMUX_COMMAND_OPEN;
1315
1316         switch (options.control_master) {
1317         case SSHCTL_MASTER_AUTO:
1318         case SSHCTL_MASTER_AUTO_ASK:
1319                 debug("auto-mux: Trying existing master");
1320                 /* FALLTHROUGH */
1321         case SSHCTL_MASTER_NO:
1322                 break;
1323         default:
1324                 return;
1325         }
1326
1327         memset(&addr, '\0', sizeof(addr));
1328         addr.sun_family = AF_UNIX;
1329         addr_len = offsetof(struct sockaddr_un, sun_path) +
1330             strlen(path) + 1;
1331
1332         if (strlcpy(addr.sun_path, path,
1333             sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
1334                 fatal("ControlPath too long");
1335
1336         if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
1337                 fatal("%s socket(): %s", __func__, strerror(errno));
1338
1339         if (connect(sock, (struct sockaddr *)&addr, addr_len) == -1) {
1340                 if (mux_command != SSHMUX_COMMAND_OPEN) {
1341                         fatal("Control socket connect(%.100s): %s", path,
1342                             strerror(errno));
1343                 }
1344                 if (errno == ENOENT)
1345                         debug("Control socket \"%.100s\" does not exist", path);
1346                 else {
1347                         error("Control socket connect(%.100s): %s", path,
1348                             strerror(errno));
1349                 }
1350                 close(sock);
1351                 return;
1352         }
1353
1354         if (stdin_null_flag) {
1355                 if ((fd = open(_PATH_DEVNULL, O_RDONLY)) == -1)
1356                         fatal("open(/dev/null): %s", strerror(errno));
1357                 if (dup2(fd, STDIN_FILENO) == -1)
1358                         fatal("dup2: %s", strerror(errno));
1359                 if (fd > STDERR_FILENO)
1360                         close(fd);
1361         }
1362
1363         term = getenv("TERM");
1364
1365         flags = 0;
1366         if (tty_flag)
1367                 flags |= SSHMUX_FLAG_TTY;
1368         if (subsystem_flag)
1369                 flags |= SSHMUX_FLAG_SUBSYS;
1370         if (options.forward_x11)
1371                 flags |= SSHMUX_FLAG_X11_FWD;
1372         if (options.forward_agent)
1373                 flags |= SSHMUX_FLAG_AGENT_FWD;
1374
1375         buffer_init(&m);
1376
1377         /* Send our command to server */
1378         buffer_put_int(&m, mux_command);
1379         buffer_put_int(&m, flags);
1380         if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1)
1381                 fatal("%s: msg_send", __func__);
1382         buffer_clear(&m);
1383
1384         /* Get authorisation status and PID of controlee */
1385         if (ssh_msg_recv(sock, &m) == -1)
1386                 fatal("%s: msg_recv", __func__);
1387         if (buffer_get_char(&m) != SSHMUX_VER)
1388                 fatal("%s: wrong version", __func__);
1389         if (buffer_get_int(&m) != 1)
1390                 fatal("Connection to master denied");
1391         control_server_pid = buffer_get_int(&m);
1392
1393         buffer_clear(&m);
1394
1395         switch (mux_command) {
1396         case SSHMUX_COMMAND_ALIVE_CHECK:
1397                 fprintf(stderr, "Master running (pid=%d)\r\n",
1398                     control_server_pid);
1399                 exit(0);
1400         case SSHMUX_COMMAND_TERMINATE:
1401                 fprintf(stderr, "Exit request sent.\r\n");
1402                 exit(0);
1403         case SSHMUX_COMMAND_OPEN:
1404                 /* continue below */
1405                 break;
1406         default:
1407                 fatal("silly mux_command %d", mux_command);
1408         }
1409
1410         /* SSHMUX_COMMAND_OPEN */
1411         buffer_put_cstring(&m, term ? term : "");
1412         buffer_append(&command, "\0", 1);
1413         buffer_put_cstring(&m, buffer_ptr(&command));
1414
1415         if (options.num_send_env == 0 || environ == NULL) {
1416                 buffer_put_int(&m, 0);
1417         } else {
1418                 /* Pass environment */
1419                 num_env = 0;
1420                 for (i = 0; environ[i] != NULL; i++)
1421                         if (env_permitted(environ[i]))
1422                                 num_env++; /* Count */
1423
1424                 buffer_put_int(&m, num_env);
1425
1426                 for (i = 0; environ[i] != NULL && num_env >= 0; i++)
1427                         if (env_permitted(environ[i])) {
1428                                 num_env--;
1429                                 buffer_put_cstring(&m, environ[i]);
1430                         }
1431         }
1432
1433         if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1)
1434                 fatal("%s: msg_send", __func__);
1435
1436         mm_send_fd(sock, STDIN_FILENO);
1437         mm_send_fd(sock, STDOUT_FILENO);
1438         mm_send_fd(sock, STDERR_FILENO);
1439
1440         /* Wait for reply, so master has a chance to gather ttymodes */
1441         buffer_clear(&m);
1442         if (ssh_msg_recv(sock, &m) == -1)
1443                 fatal("%s: msg_recv", __func__);
1444         if (buffer_get_char(&m) != SSHMUX_VER)
1445                 fatal("%s: wrong version", __func__);
1446         buffer_free(&m);
1447
1448         signal(SIGHUP, control_client_sighandler);
1449         signal(SIGINT, control_client_sighandler);
1450         signal(SIGTERM, control_client_sighandler);
1451         signal(SIGWINCH, control_client_sigrelay);
1452
1453         if (tty_flag)
1454                 enter_raw_mode();
1455
1456         /* Stick around until the controlee closes the client_fd */
1457         exitval = 0;
1458         for (;!control_client_terminate;) {
1459                 r = read(sock, &exitval, sizeof(exitval));
1460                 if (r == 0) {
1461                         debug2("Received EOF from master");
1462                         break;
1463                 }
1464                 if (r > 0)
1465                         debug2("Received exit status from master %d", exitval);
1466                 if (r == -1 && errno != EINTR)
1467                         fatal("%s: read %s", __func__, strerror(errno));
1468         }
1469
1470         if (control_client_terminate)
1471                 debug2("Exiting on signal %d", control_client_terminate);
1472
1473         close(sock);
1474
1475         leave_raw_mode();
1476
1477         if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET)
1478                 fprintf(stderr, "Connection to master closed.\r\n");
1479
1480         exit(exitval);
1481 }