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