crypto/openssh/ssh.c

   1 /* $OpenBSD: ssh.c,v 1.346 2010/08/12 21:49:44 djm Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * Ssh client program.  This program can be used to log into a remote machine.
   7  * The software supports strong authentication, encryption, and forwarding
   8  * of X11, TCP/IP, and authentication connections.
   9  *
  10  * As far as I am concerned, the code I have written for this software
  11  * can be used freely for any purpose.  Any derived versions of this
  12  * software must be clearly marked as such, and if the derived work is
  13  * incompatible with the protocol description in the RFC file, it must be
  14  * called by a name other than "ssh" or "Secure Shell".
  15  *
  16  * Copyright (c) 1999 Niels Provos.  All rights reserved.
  17  * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl.  All rights reserved.
  18  *
  19  * Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
  20  * in Canada (German citizen).
  21  *
  22  * Redistribution and use in source and binary forms, with or without
  23  * modification, are permitted provided that the following conditions
  24  * are met:
  25  * 1. Redistributions of source code must retain the above copyright
  26  *    notice, this list of conditions and the following disclaimer.
  27  * 2. Redistributions in binary form must reproduce the above copyright
  28  *    notice, this list of conditions and the following disclaimer in the
  29  *    documentation and/or other materials provided with the distribution.
  30  *
  31  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  32  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  33  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  34  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  35  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  36  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  37  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  38  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  39  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  40  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  41  */
  42
  43 #include "includes.h"
  44
  45 #include <sys/types.h>
  46 #ifdef HAVE_SYS_STAT_H
  47 # include <sys/stat.h>
  48 #endif
  49 #include <sys/resource.h>
  50 #include <sys/ioctl.h>
  51 #include <sys/param.h>
  52 #include <sys/socket.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 #include "openbsd-compat/openssl-compat.h"
  76 #include "openbsd-compat/sys-queue.h"
  77
  78 #include "xmalloc.h"
  79 #include "ssh.h"
  80 #include "ssh1.h"
  81 #include "ssh2.h"
  82 #include "canohost.h"
  83 #include "compat.h"
  84 #include "cipher.h"
  85 #include "packet.h"
  86 #include "buffer.h"
  87 #include "channels.h"
  88 #include "key.h"
  89 #include "authfd.h"
  90 #include "authfile.h"
  91 #include "pathnames.h"
  92 #include "dispatch.h"
  93 #include "clientloop.h"
  94 #include "log.h"
  95 #include "readconf.h"
  96 #include "sshconnect.h"
  97 #include "misc.h"
  98 #include "kex.h"
  99 #include "mac.h"
 100 #include "sshpty.h"
 101 #include "match.h"
 102 #include "msg.h"
 103 #include "uidswap.h"
 104 #include "roaming.h"
 105 #include "version.h"
 106
 107 #ifdef ENABLE_PKCS11
 108 #include "ssh-pkcs11.h"
 109 #endif
 110
 111 extern char *__progname;
 112
 113 /* Flag indicating whether debug mode is on.  May be set on the command line. */
 114 int debug_flag = 0;
 115
 116 /* Flag indicating whether a tty should be allocated */
 117 int tty_flag = 0;
 118 int no_tty_flag = 0;
 119 int force_tty_flag = 0;
 120
 121 /* don't exec a shell */
 122 int no_shell_flag = 0;
 123
 124 /*
 125  * Flag indicating that nothing should be read from stdin.  This can be set
 126  * on the command line.
 127  */
 128 int stdin_null_flag = 0;
 129
 130 /*
 131  * Flag indicating that the current process should be backgrounded and
 132  * a new slave launched in the foreground for ControlPersist.
 133  */
 134 int need_controlpersist_detach = 0;
 135
 136 /* Copies of flags for ControlPersist foreground slave */
 137 int ostdin_null_flag, ono_shell_flag, ono_tty_flag, otty_flag;
 138
 139 /*
 140  * Flag indicating that ssh should fork after authentication.  This is useful
 141  * so that the passphrase can be entered manually, and then ssh goes to the
 142  * background.
 143  */
 144 int fork_after_authentication_flag = 0;
 145
 146 /* forward stdio to remote host and port */
 147 char *stdio_forward_host = NULL;
 148 int stdio_forward_port = 0;
 149
 150 /*
 151  * General data structure for command line options and options configurable
 152  * in configuration files.  See readconf.h.
 153  */
 154 Options options;
 155
 156 /* optional user configfile */
 157 char *config = NULL;
 158
 159 /*
 160  * Name of the host we are connecting to.  This is the name given on the
 161  * command line, or the HostName specified for the user-supplied name in a
 162  * configuration file.
 163  */
 164 char *host;
 165
 166 /* socket address the host resolves to */
 167 struct sockaddr_storage hostaddr;
 168
 169 /* Private host keys. */
 170 Sensitive sensitive_data;
 171
 172 /* Original real UID. */
 173 uid_t original_real_uid;
 174 uid_t original_effective_uid;
 175
 176 /* command to be executed */
 177 Buffer command;
 178
 179 /* Should we execute a command or invoke a subsystem? */
 180 int subsystem_flag = 0;
 181
 182 /* # of replies received for global requests */
 183 static int remote_forward_confirms_received = 0;
 184
 185 /* pid of proxycommand child process */
 186 pid_t proxy_command_pid = 0;
 187
 188 /* mux.c */
 189 extern int muxserver_sock;
 190 extern u_int muxclient_command;
 191
 192 /* Prints a help message to the user.  This function never returns. */
 193
 194 static void
 195 usage(void)
 196 {
 197         fprintf(stderr,
 198 "usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n"
 199 "           [-D [bind_address:]port] [-e escape_char] [-F configfile]\n"
 200 "           [-I pkcs11] [-i identity_file]\n"
 201 "           [-L [bind_address:]port:host:hostport]\n"
 202 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
 203 "           [-R [bind_address:]port:host:hostport] [-S ctl_path]\n"
 204 "           [-W host:port] [-w local_tun[:remote_tun]]\n"
 205 "           [user@]hostname [command]\n"
 206         );
 207         exit(255);
 208 }
 209
 210 static int ssh_session(void);
 211 static int ssh_session2(void);
 212 static void load_public_identity_files(void);
 213
 214 /* from muxclient.c */
 215 void muxclient(const char *);
 216 void muxserver_listen(void);
 217
 218 /*
 219  * Main program for the ssh client.
 220  */
 221 int
 222 main(int ac, char **av)
 223 {
 224         int i, r, opt, exit_status, use_syslog;
 225         char *p, *cp, *line, *argv0, buf[MAXPATHLEN];
 226         struct stat st;
 227         struct passwd *pw;
 228         int dummy, timeout_ms;
 229         extern int optind, optreset;
 230         extern char *optarg;
 231         struct servent *sp;
 232         Forward fwd;
 233
 234         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 235         sanitise_stdfd();
 236
 237         __progname = ssh_get_progname(av[0]);
 238         init_rng();
 239
 240         /*
 241          * Discard other fds that are hanging around. These can cause problem
 242          * with backgrounded ssh processes started by ControlPersist.
 243          */
 244         closefrom(STDERR_FILENO + 1);
 245
 246         /*
 247          * Save the original real uid.  It will be needed later (uid-swapping
 248          * may clobber the real uid).
 249          */
 250         original_real_uid = getuid();
 251         original_effective_uid = geteuid();
 252
 253         /*
 254          * Use uid-swapping to give up root privileges for the duration of
 255          * option processing.  We will re-instantiate the rights when we are
 256          * ready to create the privileged port, and will permanently drop
 257          * them when the port has been created (actually, when the connection
 258          * has been made, as we may need to create the port several times).
 259          */
 260         PRIV_END;
 261
 262 #ifdef HAVE_SETRLIMIT
 263         /* If we are installed setuid root be careful to not drop core. */
 264         if (original_real_uid != original_effective_uid) {
 265                 struct rlimit rlim;
 266                 rlim.rlim_cur = rlim.rlim_max = 0;
 267                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 268                         fatal("setrlimit failed: %.100s", strerror(errno));
 269         }
 270 #endif
 271         /* Get user data. */
 272         pw = getpwuid(original_real_uid);
 273         if (!pw) {
 274                 logit("You don't exist, go away!");
 275                 exit(255);
 276         }
 277         /* Take a copy of the returned structure. */
 278         pw = pwcopy(pw);
 279
 280         /*
 281          * Set our umask to something reasonable, as some files are created
 282          * with the default umask.  This will make them world-readable but
 283          * writable only by the owner, which is ok for all files for which we
 284          * don't set the modes explicitly.
 285          */
 286         umask(022);
 287
 288         /*
 289          * Initialize option structure to indicate that no values have been
 290          * set.
 291          */
 292         initialize_options(&options);
 293
 294         /* Parse command-line arguments. */
 295         host = NULL;
 296         use_syslog = 0;
 297         argv0 = av[0];
 298
 299  again:
 300         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
 301             "ACD:F:I:KL:MNO:PR:S:TVw:W:XYy")) != -1) {
 302                 switch (opt) {
 303                 case '1':
 304                         options.protocol = SSH_PROTO_1;
 305                         break;
 306                 case '2':
 307                         options.protocol = SSH_PROTO_2;
 308                         break;
 309                 case '4':
 310                         options.address_family = AF_INET;
 311                         break;
 312                 case '6':
 313                         options.address_family = AF_INET6;
 314                         break;
 315                 case 'n':
 316                         stdin_null_flag = 1;
 317                         break;
 318                 case 'f':
 319                         fork_after_authentication_flag = 1;
 320                         stdin_null_flag = 1;
 321                         break;
 322                 case 'x':
 323                         options.forward_x11 = 0;
 324                         break;
 325                 case 'X':
 326                         options.forward_x11 = 1;
 327                         break;
 328                 case 'y':
 329                         use_syslog = 1;
 330                         break;
 331                 case 'Y':
 332                         options.forward_x11 = 1;
 333                         options.forward_x11_trusted = 1;
 334                         break;
 335                 case 'g':
 336                         options.gateway_ports = 1;
 337                         break;
 338                 case 'O':
 339                         if (stdio_forward_host != NULL)
 340                                 fatal("Cannot specify multiplexing "
 341                                     "command with -W");
 342                         else if (muxclient_command != 0)
 343                                 fatal("Multiplexing command already specified");
 344                         if (strcmp(optarg, "check") == 0)
 345                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
 346                         else if (strcmp(optarg, "forward") == 0)
 347                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
 348                         else if (strcmp(optarg, "exit") == 0)
 349                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
 350                         else
 351                                 fatal("Invalid multiplex command.");
 352                         break;
 353                 case 'P':       /* deprecated */
 354                         options.use_privileged_port = 0;
 355                         break;
 356                 case 'a':
 357                         options.forward_agent = 0;
 358                         break;
 359                 case 'A':
 360                         options.forward_agent = 1;
 361                         break;
 362                 case 'k':
 363                         options.gss_deleg_creds = 0;
 364                         break;
 365                 case 'K':
 366                         options.gss_authentication = 1;
 367                         options.gss_deleg_creds = 1;
 368                         break;
 369                 case 'i':
 370                         if (stat(optarg, &st) < 0) {
 371                                 fprintf(stderr, "Warning: Identity file %s "
 372                                     "not accessible: %s.\n", optarg,
 373                                     strerror(errno));
 374                                 break;
 375                         }
 376                         if (options.num_identity_files >=
 377                             SSH_MAX_IDENTITY_FILES)
 378                                 fatal("Too many identity files specified "
 379                                     "(max %d)", SSH_MAX_IDENTITY_FILES);
 380                         options.identity_files[options.num_identity_files++] =
 381                             xstrdup(optarg);
 382                         break;
 383                 case 'I':
 384 #ifdef ENABLE_PKCS11
 385                         options.pkcs11_provider = xstrdup(optarg);
 386 #else
 387                         fprintf(stderr, "no support for PKCS#11.\n");
 388 #endif
 389                         break;
 390                 case 't':
 391                         if (tty_flag)
 392                                 force_tty_flag = 1;
 393                         tty_flag = 1;
 394                         break;
 395                 case 'v':
 396                         if (debug_flag == 0) {
 397                                 debug_flag = 1;
 398                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 399                         } else {
 400                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
 401                                         options.log_level++;
 402                                 break;
 403                         }
 404                         /* FALLTHROUGH */
 405                 case 'V':
 406                         fprintf(stderr, "%s, %s\n",
 407                             SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
 408                         if (opt == 'V')
 409                                 exit(0);
 410                         break;
 411                 case 'w':
 412                         if (options.tun_open == -1)
 413                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 414                         options.tun_local = a2tun(optarg, &options.tun_remote);
 415                         if (options.tun_local == SSH_TUNID_ERR) {
 416                                 fprintf(stderr,
 417                                     "Bad tun device '%s'\n", optarg);
 418                                 exit(255);
 419                         }
 420                         break;
 421                 case 'W':
 422                         if (stdio_forward_host != NULL)
 423                                 fatal("stdio forward already specified");
 424                         if (muxclient_command != 0)
 425                                 fatal("Cannot specify stdio forward with -O");
 426                         if (parse_forward(&fwd, optarg, 1, 0)) {
 427                                 stdio_forward_host = fwd.listen_host;
 428                                 stdio_forward_port = fwd.listen_port;
 429                                 xfree(fwd.connect_host);
 430                         } else {
 431                                 fprintf(stderr,
 432                                     "Bad stdio forwarding specification '%s'\n",
 433                                     optarg);
 434                                 exit(255);
 435                         }
 436                         no_tty_flag = 1;
 437                         no_shell_flag = 1;
 438                         options.clear_forwardings = 1;
 439                         options.exit_on_forward_failure = 1;
 440                         break;
 441                 case 'q':
 442                         options.log_level = SYSLOG_LEVEL_QUIET;
 443                         break;
 444                 case 'e':
 445                         if (optarg[0] == '^' && optarg[2] == 0 &&
 446                             (u_char) optarg[1] >= 64 &&
 447                             (u_char) optarg[1] < 128)
 448                                 options.escape_char = (u_char) optarg[1] & 31;
 449                         else if (strlen(optarg) == 1)
 450                                 options.escape_char = (u_char) optarg[0];
 451                         else if (strcmp(optarg, "none") == 0)
 452                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 453                         else {
 454                                 fprintf(stderr, "Bad escape character '%s'.\n",
 455                                     optarg);
 456                                 exit(255);
 457                         }
 458                         break;
 459                 case 'c':
 460                         if (ciphers_valid(optarg)) {
 461                                 /* SSH2 only */
 462                                 options.ciphers = xstrdup(optarg);
 463                                 options.cipher = SSH_CIPHER_INVALID;
 464                         } else {
 465                                 /* SSH1 only */
 466                                 options.cipher = cipher_number(optarg);
 467                                 if (options.cipher == -1) {
 468                                         fprintf(stderr,
 469                                             "Unknown cipher type '%s'\n",
 470                                             optarg);
 471                                         exit(255);
 472                                 }
 473                                 if (options.cipher == SSH_CIPHER_3DES)
 474                                         options.ciphers = "3des-cbc";
 475                                 else if (options.cipher == SSH_CIPHER_BLOWFISH)
 476                                         options.ciphers = "blowfish-cbc";
 477                                 else
 478                                         options.ciphers = (char *)-1;
 479                         }
 480                         break;
 481                 case 'm':
 482                         if (mac_valid(optarg))
 483                                 options.macs = xstrdup(optarg);
 484                         else {
 485                                 fprintf(stderr, "Unknown mac type '%s'\n",
 486                                     optarg);
 487                                 exit(255);
 488                         }
 489                         break;
 490                 case 'M':
 491                         if (options.control_master == SSHCTL_MASTER_YES)
 492                                 options.control_master = SSHCTL_MASTER_ASK;
 493                         else
 494                                 options.control_master = SSHCTL_MASTER_YES;
 495                         break;
 496                 case 'p':
 497                         options.port = a2port(optarg);
 498                         if (options.port <= 0) {
 499                                 fprintf(stderr, "Bad port '%s'\n", optarg);
 500                                 exit(255);
 501                         }
 502                         break;
 503                 case 'l':
 504                         options.user = optarg;
 505                         break;
 506
 507                 case 'L':
 508                         if (parse_forward(&fwd, optarg, 0, 0))
 509                                 add_local_forward(&options, &fwd);
 510                         else {
 511                                 fprintf(stderr,
 512                                     "Bad local forwarding specification '%s'\n",
 513                                     optarg);
 514                                 exit(255);
 515                         }
 516                         break;
 517
 518                 case 'R':
 519                         if (parse_forward(&fwd, optarg, 0, 1)) {
 520                                 add_remote_forward(&options, &fwd);
 521                         } else {
 522                                 fprintf(stderr,
 523                                     "Bad remote forwarding specification "
 524                                     "'%s'\n", optarg);
 525                                 exit(255);
 526                         }
 527                         break;
 528
 529                 case 'D':
 530                         if (parse_forward(&fwd, optarg, 1, 0)) {
 531                                 add_local_forward(&options, &fwd);
 532                         } else {
 533                                 fprintf(stderr,
 534                                     "Bad dynamic forwarding specification "
 535                                     "'%s'\n", optarg);
 536                                 exit(255);
 537                         }
 538                         break;
 539
 540                 case 'C':
 541                         options.compression = 1;
 542                         break;
 543                 case 'N':
 544                         no_shell_flag = 1;
 545                         no_tty_flag = 1;
 546                         break;
 547                 case 'T':
 548                         no_tty_flag = 1;
 549                         break;
 550                 case 'o':
 551                         dummy = 1;
 552                         line = xstrdup(optarg);
 553                         if (process_config_line(&options, host ? host : "",
 554                             line, "command-line", 0, &dummy) != 0)
 555                                 exit(255);
 556                         xfree(line);
 557                         break;
 558                 case 's':
 559                         subsystem_flag = 1;
 560                         break;
 561                 case 'S':
 562                         if (options.control_path != NULL)
 563                                 free(options.control_path);
 564                         options.control_path = xstrdup(optarg);
 565                         break;
 566                 case 'b':
 567                         options.bind_address = optarg;
 568                         break;
 569                 case 'F':
 570                         config = optarg;
 571                         break;
 572                 default:
 573                         usage();
 574                 }
 575         }
 576
 577         ac -= optind;
 578         av += optind;
 579
 580         if (ac > 0 && !host) {
 581                 if (strrchr(*av, '@')) {
 582                         p = xstrdup(*av);
 583                         cp = strrchr(p, '@');
 584                         if (cp == NULL || cp == p)
 585                                 usage();
 586                         options.user = p;
 587                         *cp = '\0';
 588                         host = ++cp;
 589                 } else
 590                         host = *av;
 591                 if (ac > 1) {
 592                         optind = optreset = 1;
 593                         goto again;
 594                 }
 595                 ac--, av++;
 596         }
 597
 598         /* Check that we got a host name. */
 599         if (!host)
 600                 usage();
 601
 602         SSLeay_add_all_algorithms();
 603         ERR_load_crypto_strings();
 604
 605         /* Initialize the command to execute on remote host. */
 606         buffer_init(&command);
 607
 608         /*
 609          * Save the command to execute on the remote host in a buffer. There
 610          * is no limit on the length of the command, except by the maximum
 611          * packet size.  Also sets the tty flag if there is no command.
 612          */
 613         if (!ac) {
 614                 /* No command specified - execute shell on a tty. */
 615                 tty_flag = 1;
 616                 if (subsystem_flag) {
 617                         fprintf(stderr,
 618                             "You must specify a subsystem to invoke.\n");
 619                         usage();
 620                 }
 621         } else {
 622                 /* A command has been specified.  Store it into the buffer. */
 623                 for (i = 0; i < ac; i++) {
 624                         if (i)
 625                                 buffer_append(&command, " ", 1);
 626                         buffer_append(&command, av[i], strlen(av[i]));
 627                 }
 628         }
 629
 630         /* Cannot fork to background if no command. */
 631         if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
 632             !no_shell_flag)
 633                 fatal("Cannot fork into background without a command "
 634                     "to execute.");
 635
 636         /* Allocate a tty by default if no command specified. */
 637         if (buffer_len(&command) == 0)
 638                 tty_flag = 1;
 639
 640         /* Force no tty */
 641         if (no_tty_flag || muxclient_command != 0)
 642                 tty_flag = 0;
 643         /* Do not allocate a tty if stdin is not a tty. */
 644         if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) {
 645                 if (tty_flag)
 646                         logit("Pseudo-terminal will not be allocated because "
 647                             "stdin is not a terminal.");
 648                 tty_flag = 0;
 649         }
 650
 651         /*
 652          * Initialize "log" output.  Since we are the client all output
 653          * actually goes to stderr.
 654          */
 655         log_init(argv0,
 656             options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
 657             SYSLOG_FACILITY_USER, !use_syslog);
 658
 659         /*
 660          * Read per-user configuration file.  Ignore the system wide config
 661          * file if the user specifies a config file on the command line.
 662          */
 663         if (config != NULL) {
 664                 if (!read_config_file(config, host, &options, 0))
 665                         fatal("Can't open user config file %.100s: "
 666                             "%.100s", config, strerror(errno));
 667         } else {
 668                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
 669                     _PATH_SSH_USER_CONFFILE);
 670                 if (r > 0 && (size_t)r < sizeof(buf))
 671                         (void)read_config_file(buf, host, &options, 1);
 672
 673                 /* Read systemwide configuration file after use config. */
 674                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host,
 675                     &options, 0);
 676         }
 677
 678         /* Fill configuration defaults. */
 679         fill_default_options(&options);
 680
 681         channel_set_af(options.address_family);
 682
 683         /* reinit */
 684         log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
 685
 686         seed_rng();
 687
 688         if (options.user == NULL)
 689                 options.user = xstrdup(pw->pw_name);
 690
 691         /* Get default port if port has not been set. */
 692         if (options.port == 0) {
 693                 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
 694                 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT;
 695         }
 696
 697         if (options.hostname != NULL) {
 698                 host = percent_expand(options.hostname,
 699                     "h", host, (char *)NULL);
 700         }
 701
 702         if (options.local_command != NULL) {
 703                 char thishost[NI_MAXHOST];
 704
 705                 if (gethostname(thishost, sizeof(thishost)) == -1)
 706                         fatal("gethostname: %s", strerror(errno));
 707                 snprintf(buf, sizeof(buf), "%d", options.port);
 708                 debug3("expanding LocalCommand: %s", options.local_command);
 709                 cp = options.local_command;
 710                 options.local_command = percent_expand(cp, "d", pw->pw_dir,
 711                     "h", host, "l", thishost, "n", host, "r", options.user,
 712                     "p", buf, "u", pw->pw_name, (char *)NULL);
 713                 debug3("expanded LocalCommand: %s", options.local_command);
 714                 xfree(cp);
 715         }
 716
 717         /* force lowercase for hostkey matching */
 718         if (options.host_key_alias != NULL) {
 719                 for (p = options.host_key_alias; *p; p++)
 720                         if (isupper(*p))
 721                                 *p = (char)tolower(*p);
 722         }
 723
 724         if (options.proxy_command != NULL &&
 725             strcmp(options.proxy_command, "none") == 0) {
 726                 xfree(options.proxy_command);
 727                 options.proxy_command = NULL;
 728         }
 729         if (options.control_path != NULL &&
 730             strcmp(options.control_path, "none") == 0) {
 731                 xfree(options.control_path);
 732                 options.control_path = NULL;
 733         }
 734
 735         if (options.control_path != NULL) {
 736                 char thishost[NI_MAXHOST];
 737
 738                 if (gethostname(thishost, sizeof(thishost)) == -1)
 739                         fatal("gethostname: %s", strerror(errno));
 740                 snprintf(buf, sizeof(buf), "%d", options.port);
 741                 cp = tilde_expand_filename(options.control_path,
 742                     original_real_uid);
 743                 xfree(options.control_path);
 744                 options.control_path = percent_expand(cp, "p", buf, "h", host,
 745                     "r", options.user, "l", thishost, (char *)NULL);
 746                 xfree(cp);
 747         }
 748         if (muxclient_command != 0 && options.control_path == NULL)
 749                 fatal("No ControlPath specified for \"-O\" command");
 750         if (options.control_path != NULL)
 751                 muxclient(options.control_path);
 752
 753         timeout_ms = options.connection_timeout * 1000;
 754
 755         /* Open a connection to the remote host. */
 756         if (ssh_connect(host, &hostaddr, options.port,
 757             options.address_family, options.connection_attempts, &timeout_ms,
 758             options.tcp_keep_alive,
 759 #ifdef HAVE_CYGWIN
 760             options.use_privileged_port,
 761 #else
 762             original_effective_uid == 0 && options.use_privileged_port,
 763 #endif
 764             options.proxy_command) != 0)
 765                 exit(255);
 766
 767         if (timeout_ms > 0)
 768                 debug3("timeout: %d ms remain after connect", timeout_ms);
 769
 770         /*
 771          * If we successfully made the connection, load the host private key
 772          * in case we will need it later for combined rsa-rhosts
 773          * authentication. This must be done before releasing extra
 774          * privileges, because the file is only readable by root.
 775          * If we cannot access the private keys, load the public keys
 776          * instead and try to execute the ssh-keysign helper instead.
 777          */
 778         sensitive_data.nkeys = 0;
 779         sensitive_data.keys = NULL;
 780         sensitive_data.external_keysign = 0;
 781         if (options.rhosts_rsa_authentication ||
 782             options.hostbased_authentication) {
 783                 sensitive_data.nkeys = 5;
 784                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
 785                     sizeof(Key));
 786
 787                 PRIV_START;
 788                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
 789                     _PATH_HOST_KEY_FILE, "", NULL, NULL);
 790                 sensitive_data.keys[1] = key_load_private_cert(KEY_DSA,
 791                     _PATH_HOST_DSA_KEY_FILE, "", NULL);
 792                 sensitive_data.keys[2] = key_load_private_cert(KEY_RSA,
 793                     _PATH_HOST_RSA_KEY_FILE, "", NULL);
 794                 sensitive_data.keys[3] = key_load_private_type(KEY_DSA,
 795                     _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
 796                 sensitive_data.keys[4] = key_load_private_type(KEY_RSA,
 797                     _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
 798                 PRIV_END;
 799
 800                 if (options.hostbased_authentication == 1 &&
 801                     sensitive_data.keys[0] == NULL &&
 802                     sensitive_data.keys[3] == NULL &&
 803                     sensitive_data.keys[4] == NULL) {
 804                         sensitive_data.keys[1] = key_load_cert(
 805                             _PATH_HOST_DSA_KEY_FILE);
 806                         sensitive_data.keys[2] = key_load_cert(
 807                             _PATH_HOST_RSA_KEY_FILE);
 808                         sensitive_data.keys[3] = key_load_public(
 809                             _PATH_HOST_DSA_KEY_FILE, NULL);
 810                         sensitive_data.keys[4] = key_load_public(
 811                             _PATH_HOST_RSA_KEY_FILE, NULL);
 812                         sensitive_data.external_keysign = 1;
 813                 }
 814         }
 815         /*
 816          * Get rid of any extra privileges that we may have.  We will no
 817          * longer need them.  Also, extra privileges could make it very hard
 818          * to read identity files and other non-world-readable files from the
 819          * user's home directory if it happens to be on a NFS volume where
 820          * root is mapped to nobody.
 821          */
 822         if (original_effective_uid == 0) {
 823                 PRIV_START;
 824                 permanently_set_uid(pw);
 825         }
 826
 827         /*
 828          * Now that we are back to our own permissions, create ~/.ssh
 829          * directory if it doesn't already exist.
 830          */
 831         r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
 832             strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
 833         if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0)
 834                 if (mkdir(buf, 0700) < 0)
 835                         error("Could not create directory '%.200s'.", buf);
 836
 837         /* load options.identity_files */
 838         load_public_identity_files();
 839
 840         /* Expand ~ in known host file names. */
 841         /* XXX mem-leaks: */
 842         options.system_hostfile =
 843             tilde_expand_filename(options.system_hostfile, original_real_uid);
 844         options.user_hostfile =
 845             tilde_expand_filename(options.user_hostfile, original_real_uid);
 846         options.system_hostfile2 =
 847             tilde_expand_filename(options.system_hostfile2, original_real_uid);
 848         options.user_hostfile2 =
 849             tilde_expand_filename(options.user_hostfile2, original_real_uid);
 850
 851         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
 852
 853         /* Log into the remote system.  Never returns if the login fails. */
 854         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
 855             pw, timeout_ms);
 856
 857         if (packet_connection_is_on_socket()) {
 858                 verbose("Authenticated to %s ([%s]:%d).", host,
 859                     get_remote_ipaddr(), get_remote_port());
 860         } else {
 861                 verbose("Authenticated to %s (via proxy).", host);
 862         }
 863
 864         /* We no longer need the private host keys.  Clear them now. */
 865         if (sensitive_data.nkeys != 0) {
 866                 for (i = 0; i < sensitive_data.nkeys; i++) {
 867                         if (sensitive_data.keys[i] != NULL) {
 868                                 /* Destroys contents safely */
 869                                 debug3("clear hostkey %d", i);
 870                                 key_free(sensitive_data.keys[i]);
 871                                 sensitive_data.keys[i] = NULL;
 872                         }
 873                 }
 874                 xfree(sensitive_data.keys);
 875         }
 876         for (i = 0; i < options.num_identity_files; i++) {
 877                 if (options.identity_files[i]) {
 878                         xfree(options.identity_files[i]);
 879                         options.identity_files[i] = NULL;
 880                 }
 881                 if (options.identity_keys[i]) {
 882                         key_free(options.identity_keys[i]);
 883                         options.identity_keys[i] = NULL;
 884                 }
 885         }
 886
 887         exit_status = compat20 ? ssh_session2() : ssh_session();
 888         packet_close();
 889
 890         if (options.control_path != NULL && muxserver_sock != -1)
 891                 unlink(options.control_path);
 892
 893         /*
 894          * Send SIGHUP to proxy command if used. We don't wait() in
 895          * case it hangs and instead rely on init to reap the child
 896          */
 897         if (proxy_command_pid > 1)
 898                 kill(proxy_command_pid, SIGHUP);
 899
 900         return exit_status;
 901 }
 902
 903 static void
 904 control_persist_detach(void)
 905 {
 906         pid_t pid;
 907         int devnull;
 908
 909         debug("%s: backgrounding master process", __func__);
 910
 911         /*
 912          * master (current process) into the background, and make the
 913          * foreground process a client of the backgrounded master.
 914          */
 915         switch ((pid = fork())) {
 916         case -1:
 917                 fatal("%s: fork: %s", __func__, strerror(errno));
 918         case 0:
 919                 /* Child: master process continues mainloop */
 920                 break;
 921         default:
 922                 /* Parent: set up mux slave to connect to backgrounded master */
 923                 debug2("%s: background process is %ld", __func__, (long)pid);
 924                 stdin_null_flag = ostdin_null_flag;
 925                 no_shell_flag = ono_shell_flag;
 926                 no_tty_flag = ono_tty_flag;
 927                 tty_flag = otty_flag;
 928                 close(muxserver_sock);
 929                 muxserver_sock = -1;
 930                 muxclient(options.control_path);
 931                 /* muxclient() doesn't return on success. */
 932                 fatal("Failed to connect to new control master");
 933         }
 934         if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
 935                 error("%s: open(\"/dev/null\"): %s", __func__,
 936                     strerror(errno));
 937         } else {
 938                 if (dup2(devnull, STDIN_FILENO) == -1 ||
 939                     dup2(devnull, STDOUT_FILENO) == -1)
 940                         error("%s: dup2: %s", __func__, strerror(errno));
 941                 if (devnull > STDERR_FILENO)
 942                         close(devnull);
 943         }
 944 }
 945
 946 /* Do fork() after authentication. Used by "ssh -f" */
 947 static void
 948 fork_postauth(void)
 949 {
 950         if (need_controlpersist_detach)
 951                 control_persist_detach();
 952         debug("forking to background");
 953         fork_after_authentication_flag = 0;
 954         if (daemon(1, 1) < 0)
 955                 fatal("daemon() failed: %.200s", strerror(errno));
 956 }
 957
 958 /* Callback for remote forward global requests */
 959 static void
 960 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
 961 {
 962         Forward *rfwd = (Forward *)ctxt;
 963
 964         /* XXX verbose() on failure? */
 965         debug("remote forward %s for: listen %d, connect %s:%d",
 966             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
 967             rfwd->listen_port, rfwd->connect_host, rfwd->connect_port);
 968         if (type == SSH2_MSG_REQUEST_SUCCESS && rfwd->listen_port == 0) {
 969                 rfwd->allocated_port = packet_get_int();
 970                 logit("Allocated port %u for remote forward to %s:%d",
 971                     rfwd->allocated_port,
 972                     rfwd->connect_host, rfwd->connect_port);
 973         }
 974
 975         if (type == SSH2_MSG_REQUEST_FAILURE) {
 976                 if (options.exit_on_forward_failure)
 977                         fatal("Error: remote port forwarding failed for "
 978                             "listen port %d", rfwd->listen_port);
 979                 else
 980                         logit("Warning: remote port forwarding failed for "
 981                             "listen port %d", rfwd->listen_port);
 982         }
 983         if (++remote_forward_confirms_received == options.num_remote_forwards) {
 984                 debug("All remote forwarding requests processed");
 985                 if (fork_after_authentication_flag)
 986                         fork_postauth();
 987         }
 988 }
 989
 990 static void
 991 client_cleanup_stdio_fwd(int id, void *arg)
 992 {
 993         debug("stdio forwarding: done");
 994         cleanup_exit(0);
 995 }
 996
 997 static int
 998 client_setup_stdio_fwd(const char *host_to_connect, u_short port_to_connect)
 999 {
1000         Channel *c;
1001         int in, out;
1002
1003         debug3("client_setup_stdio_fwd %s:%d", host_to_connect,
1004             port_to_connect);
1005
1006         in = dup(STDIN_FILENO);
1007         out = dup(STDOUT_FILENO);
1008         if (in < 0 || out < 0)
1009                 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1010
1011         if ((c = channel_connect_stdio_fwd(host_to_connect, port_to_connect,
1012             in, out)) == NULL)
1013                 return 0;
1014         channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
1015         return 1;
1016 }
1017
1018 static void
1019 ssh_init_forwarding(void)
1020 {
1021         int success = 0;
1022         int i;
1023
1024         if (stdio_forward_host != NULL) {
1025                 if (!compat20) {
1026                         fatal("stdio forwarding require Protocol 2");
1027                 }
1028                 if (!client_setup_stdio_fwd(stdio_forward_host,
1029                     stdio_forward_port))
1030                         fatal("Failed to connect in stdio forward mode.");
1031         }
1032
1033         /* Initiate local TCP/IP port forwardings. */
1034         for (i = 0; i < options.num_local_forwards; i++) {
1035                 debug("Local connections to %.200s:%d forwarded to remote "
1036                     "address %.200s:%d",
1037                     (options.local_forwards[i].listen_host == NULL) ?
1038                     (options.gateway_ports ? "*" : "LOCALHOST") :
1039                     options.local_forwards[i].listen_host,
1040                     options.local_forwards[i].listen_port,
1041                     options.local_forwards[i].connect_host,
1042                     options.local_forwards[i].connect_port);
1043                 success += channel_setup_local_fwd_listener(
1044                     options.local_forwards[i].listen_host,
1045                     options.local_forwards[i].listen_port,
1046                     options.local_forwards[i].connect_host,
1047                     options.local_forwards[i].connect_port,
1048                     options.gateway_ports);
1049         }
1050         if (i > 0 && success != i && options.exit_on_forward_failure)
1051                 fatal("Could not request local forwarding.");
1052         if (i > 0 && success == 0)
1053                 error("Could not request local forwarding.");
1054
1055         /* Initiate remote TCP/IP port forwardings. */
1056         for (i = 0; i < options.num_remote_forwards; i++) {
1057                 debug("Remote connections from %.200s:%d forwarded to "
1058                     "local address %.200s:%d",
1059                     (options.remote_forwards[i].listen_host == NULL) ?
1060                     "LOCALHOST" : options.remote_forwards[i].listen_host,
1061                     options.remote_forwards[i].listen_port,
1062                     options.remote_forwards[i].connect_host,
1063                     options.remote_forwards[i].connect_port);
1064                 if (channel_request_remote_forwarding(
1065                     options.remote_forwards[i].listen_host,
1066                     options.remote_forwards[i].listen_port,
1067                     options.remote_forwards[i].connect_host,
1068                     options.remote_forwards[i].connect_port) < 0) {
1069                         if (options.exit_on_forward_failure)
1070                                 fatal("Could not request remote forwarding.");
1071                         else
1072                                 logit("Warning: Could not request remote "
1073                                     "forwarding.");
1074                 }
1075                 client_register_global_confirm(ssh_confirm_remote_forward,
1076                     &options.remote_forwards[i]);
1077         }
1078
1079         /* Initiate tunnel forwarding. */
1080         if (options.tun_open != SSH_TUNMODE_NO) {
1081                 if (client_request_tun_fwd(options.tun_open,
1082                     options.tun_local, options.tun_remote) == -1) {
1083                         if (options.exit_on_forward_failure)
1084                                 fatal("Could not request tunnel forwarding.");
1085                         else
1086                                 error("Could not request tunnel forwarding.");
1087                 }
1088         }
1089 }
1090
1091 static void
1092 check_agent_present(void)
1093 {
1094         if (options.forward_agent) {
1095                 /* Clear agent forwarding if we don't have an agent. */
1096                 if (!ssh_agent_present())
1097                         options.forward_agent = 0;
1098         }
1099 }
1100
1101 static int
1102 ssh_session(void)
1103 {
1104         int type;
1105         int interactive = 0;
1106         int have_tty = 0;
1107         struct winsize ws;
1108         char *cp;
1109         const char *display;
1110
1111         /* Enable compression if requested. */
1112         if (options.compression) {
1113                 debug("Requesting compression at level %d.",
1114                     options.compression_level);
1115
1116                 if (options.compression_level < 1 ||
1117                     options.compression_level > 9)
1118                         fatal("Compression level must be from 1 (fast) to "
1119                             "9 (slow, best).");
1120
1121                 /* Send the request. */
1122                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
1123                 packet_put_int(options.compression_level);
1124                 packet_send();
1125                 packet_write_wait();
1126                 type = packet_read();
1127                 if (type == SSH_SMSG_SUCCESS)
1128                         packet_start_compression(options.compression_level);
1129                 else if (type == SSH_SMSG_FAILURE)
1130                         logit("Warning: Remote host refused compression.");
1131                 else
1132                         packet_disconnect("Protocol error waiting for "
1133                             "compression response.");
1134         }
1135         /* Allocate a pseudo tty if appropriate. */
1136         if (tty_flag) {
1137                 debug("Requesting pty.");
1138
1139                 /* Start the packet. */
1140                 packet_start(SSH_CMSG_REQUEST_PTY);
1141
1142                 /* Store TERM in the packet.  There is no limit on the
1143                    length of the string. */
1144                 cp = getenv("TERM");
1145                 if (!cp)
1146                         cp = "";
1147                 packet_put_cstring(cp);
1148
1149                 /* Store window size in the packet. */
1150                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
1151                         memset(&ws, 0, sizeof(ws));
1152                 packet_put_int((u_int)ws.ws_row);
1153                 packet_put_int((u_int)ws.ws_col);
1154                 packet_put_int((u_int)ws.ws_xpixel);
1155                 packet_put_int((u_int)ws.ws_ypixel);
1156
1157                 /* Store tty modes in the packet. */
1158                 tty_make_modes(fileno(stdin), NULL);
1159
1160                 /* Send the packet, and wait for it to leave. */
1161                 packet_send();
1162                 packet_write_wait();
1163
1164                 /* Read response from the server. */
1165                 type = packet_read();
1166                 if (type == SSH_SMSG_SUCCESS) {
1167                         interactive = 1;
1168                         have_tty = 1;
1169                 } else if (type == SSH_SMSG_FAILURE)
1170                         logit("Warning: Remote host failed or refused to "
1171                             "allocate a pseudo tty.");
1172                 else
1173                         packet_disconnect("Protocol error waiting for pty "
1174                             "request response.");
1175         }
1176         /* Request X11 forwarding if enabled and DISPLAY is set. */
1177         display = getenv("DISPLAY");
1178         if (options.forward_x11 && display != NULL) {
1179                 char *proto, *data;
1180                 /* Get reasonable local authentication information. */
1181                 client_x11_get_proto(display, options.xauth_location,
1182                     options.forward_x11_trusted,
1183                     options.forward_x11_timeout,
1184                     &proto, &data);
1185                 /* Request forwarding with authentication spoofing. */
1186                 debug("Requesting X11 forwarding with authentication "
1187                     "spoofing.");
1188                 x11_request_forwarding_with_spoofing(0, display, proto, data);
1189
1190                 /* Read response from the server. */
1191                 type = packet_read();
1192                 if (type == SSH_SMSG_SUCCESS) {
1193                         interactive = 1;
1194                 } else if (type == SSH_SMSG_FAILURE) {
1195                         logit("Warning: Remote host denied X11 forwarding.");
1196                 } else {
1197                         packet_disconnect("Protocol error waiting for X11 "
1198                             "forwarding");
1199                 }
1200         }
1201         /* Tell the packet module whether this is an interactive session. */
1202         packet_set_interactive(interactive);
1203
1204         /* Request authentication agent forwarding if appropriate. */
1205         check_agent_present();
1206
1207         if (options.forward_agent) {
1208                 debug("Requesting authentication agent forwarding.");
1209                 auth_request_forwarding();
1210
1211                 /* Read response from the server. */
1212                 type = packet_read();
1213                 packet_check_eom();
1214                 if (type != SSH_SMSG_SUCCESS)
1215                         logit("Warning: Remote host denied authentication agent forwarding.");
1216         }
1217
1218         /* Initiate port forwardings. */
1219         ssh_init_forwarding();
1220
1221         /* Execute a local command */
1222         if (options.local_command != NULL &&
1223             options.permit_local_command)
1224                 ssh_local_cmd(options.local_command);
1225
1226         /*
1227          * If requested and we are not interested in replies to remote
1228          * forwarding requests, then let ssh continue in the background.
1229          */
1230         if (fork_after_authentication_flag) {
1231                 if (options.exit_on_forward_failure &&
1232                     options.num_remote_forwards > 0) {
1233                         debug("deferring postauth fork until remote forward "
1234                             "confirmation received");
1235                 } else
1236                         fork_postauth();
1237         }
1238
1239         /*
1240          * If a command was specified on the command line, execute the
1241          * command now. Otherwise request the server to start a shell.
1242          */
1243         if (buffer_len(&command) > 0) {
1244                 int len = buffer_len(&command);
1245                 if (len > 900)
1246                         len = 900;
1247                 debug("Sending command: %.*s", len,
1248                     (u_char *)buffer_ptr(&command));
1249                 packet_start(SSH_CMSG_EXEC_CMD);
1250                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1251                 packet_send();
1252                 packet_write_wait();
1253         } else {
1254                 debug("Requesting shell.");
1255                 packet_start(SSH_CMSG_EXEC_SHELL);
1256                 packet_send();
1257                 packet_write_wait();
1258         }
1259
1260         /* Enter the interactive session. */
1261         return client_loop(have_tty, tty_flag ?
1262             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1263 }
1264
1265 /* request pty/x11/agent/tcpfwd/shell for channel */
1266 static void
1267 ssh_session2_setup(int id, int success, void *arg)
1268 {
1269         extern char **environ;
1270         const char *display;
1271         int interactive = tty_flag;
1272
1273         if (!success)
1274                 return; /* No need for error message, channels code sens one */
1275
1276         display = getenv("DISPLAY");
1277         if (options.forward_x11 && display != NULL) {
1278                 char *proto, *data;
1279                 /* Get reasonable local authentication information. */
1280                 client_x11_get_proto(display, options.xauth_location,
1281                     options.forward_x11_trusted,
1282                     options.forward_x11_timeout, &proto, &data);
1283                 /* Request forwarding with authentication spoofing. */
1284                 debug("Requesting X11 forwarding with authentication "
1285                     "spoofing.");
1286                 x11_request_forwarding_with_spoofing(id, display, proto, data);
1287                 interactive = 1;
1288                 /* XXX wait for reply */
1289         }
1290
1291         check_agent_present();
1292         if (options.forward_agent) {
1293                 debug("Requesting authentication agent forwarding.");
1294                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1295                 packet_send();
1296         }
1297
1298         client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1299             NULL, fileno(stdin), &command, environ);
1300
1301         packet_set_interactive(interactive);
1302 }
1303
1304 /* open new channel for a session */
1305 static int
1306 ssh_session2_open(void)
1307 {
1308         Channel *c;
1309         int window, packetmax, in, out, err;
1310
1311         if (stdin_null_flag) {
1312                 in = open(_PATH_DEVNULL, O_RDONLY);
1313         } else {
1314                 in = dup(STDIN_FILENO);
1315         }
1316         out = dup(STDOUT_FILENO);
1317         err = dup(STDERR_FILENO);
1318
1319         if (in < 0 || out < 0 || err < 0)
1320                 fatal("dup() in/out/err failed");
1321
1322         /* enable nonblocking unless tty */
1323         if (!isatty(in))
1324                 set_nonblock(in);
1325         if (!isatty(out))
1326                 set_nonblock(out);
1327         if (!isatty(err))
1328                 set_nonblock(err);
1329
1330         window = CHAN_SES_WINDOW_DEFAULT;
1331         packetmax = CHAN_SES_PACKET_DEFAULT;
1332         if (tty_flag) {
1333                 window >>= 1;
1334                 packetmax >>= 1;
1335         }
1336         c = channel_new(
1337             "session", SSH_CHANNEL_OPENING, in, out, err,
1338             window, packetmax, CHAN_EXTENDED_WRITE,
1339             "client-session", /*nonblock*/0);
1340
1341         debug3("ssh_session2_open: channel_new: %d", c->self);
1342
1343         channel_send_open(c->self);
1344         if (!no_shell_flag)
1345                 channel_register_open_confirm(c->self,
1346                     ssh_session2_setup, NULL);
1347
1348         return c->self;
1349 }
1350
1351 static int
1352 ssh_session2(void)
1353 {
1354         int id = -1;
1355
1356         /* XXX should be pre-session */
1357         ssh_init_forwarding();
1358
1359         /* Start listening for multiplex clients */
1360         muxserver_listen();
1361
1362         /*
1363          * If we are in control persist mode, then prepare to background
1364          * ourselves and have a foreground client attach as a control
1365          * slave. NB. we must save copies of the flags that we override for
1366          * the backgrounding, since we defer attachment of the slave until
1367          * after the connection is fully established (in particular,
1368          * async rfwd replies have been received for ExitOnForwardFailure).
1369          */
1370         if (options.control_persist && muxserver_sock != -1) {
1371                 ostdin_null_flag = stdin_null_flag;
1372                 ono_shell_flag = no_shell_flag;
1373                 ono_tty_flag = no_tty_flag;
1374                 otty_flag = tty_flag;
1375                 stdin_null_flag = 1;
1376                 no_shell_flag = 1;
1377                 no_tty_flag = 1;
1378                 tty_flag = 0;
1379                 if (!fork_after_authentication_flag)
1380                         need_controlpersist_detach = 1;
1381                 fork_after_authentication_flag = 1;
1382         }
1383
1384         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1385                 id = ssh_session2_open();
1386
1387         /* If we don't expect to open a new session, then disallow it */
1388         if (options.control_master == SSHCTL_MASTER_NO &&
1389             (datafellows & SSH_NEW_OPENSSH)) {
1390                 debug("Requesting no-more-sessions@openssh.com");
1391                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1392                 packet_put_cstring("no-more-sessions@openssh.com");
1393                 packet_put_char(0);
1394                 packet_send();
1395         }
1396
1397         /* Execute a local command */
1398         if (options.local_command != NULL &&
1399             options.permit_local_command)
1400                 ssh_local_cmd(options.local_command);
1401
1402         /*
1403          * If requested and we are not interested in replies to remote
1404          * forwarding requests, then let ssh continue in the background.
1405          */
1406         if (fork_after_authentication_flag) {
1407                 if (options.exit_on_forward_failure &&
1408                     options.num_remote_forwards > 0) {
1409                         debug("deferring postauth fork until remote forward "
1410                             "confirmation received");
1411                 } else
1412                         fork_postauth();
1413         }
1414
1415         if (options.use_roaming)
1416                 request_roaming();
1417
1418         return client_loop(tty_flag, tty_flag ?
1419             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1420 }
1421
1422 static void
1423 load_public_identity_files(void)
1424 {
1425         char *filename, *cp, thishost[NI_MAXHOST];
1426         char *pwdir = NULL, *pwname = NULL;
1427         int i = 0;
1428         Key *public;
1429         struct passwd *pw;
1430         u_int n_ids;
1431         char *identity_files[SSH_MAX_IDENTITY_FILES];
1432         Key *identity_keys[SSH_MAX_IDENTITY_FILES];
1433 #ifdef ENABLE_PKCS11
1434         Key **keys;
1435         int nkeys;
1436 #endif /* PKCS11 */
1437
1438         n_ids = 0;
1439         bzero(identity_files, sizeof(identity_files));
1440         bzero(identity_keys, sizeof(identity_keys));
1441
1442 #ifdef ENABLE_PKCS11
1443         if (options.pkcs11_provider != NULL &&
1444             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1445             (pkcs11_init(!options.batch_mode) == 0) &&
1446             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
1447             &keys)) > 0) {
1448                 for (i = 0; i < nkeys; i++) {
1449                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
1450                                 key_free(keys[i]);
1451                                 continue;
1452                         }
1453                         identity_keys[n_ids] = keys[i];
1454                         identity_files[n_ids] =
1455                             xstrdup(options.pkcs11_provider); /* XXX */
1456                         n_ids++;
1457                 }
1458                 xfree(keys);
1459         }
1460 #endif /* ENABLE_PKCS11 */
1461         if ((pw = getpwuid(original_real_uid)) == NULL)
1462                 fatal("load_public_identity_files: getpwuid failed");
1463         pwname = xstrdup(pw->pw_name);
1464         pwdir = xstrdup(pw->pw_dir);
1465         if (gethostname(thishost, sizeof(thishost)) == -1)
1466                 fatal("load_public_identity_files: gethostname: %s",
1467                     strerror(errno));
1468         for (i = 0; i < options.num_identity_files; i++) {
1469                 if (n_ids >= SSH_MAX_IDENTITY_FILES) {
1470                         xfree(options.identity_files[i]);
1471                         continue;
1472                 }
1473                 cp = tilde_expand_filename(options.identity_files[i],
1474                     original_real_uid);
1475                 filename = percent_expand(cp, "d", pwdir,
1476                     "u", pwname, "l", thishost, "h", host,
1477                     "r", options.user, (char *)NULL);
1478                 xfree(cp);
1479                 public = key_load_public(filename, NULL);
1480                 debug("identity file %s type %d", filename,
1481                     public ? public->type : -1);
1482                 xfree(options.identity_files[i]);
1483                 identity_files[n_ids] = filename;
1484                 identity_keys[n_ids] = public;
1485
1486                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
1487                         continue;
1488
1489                 /* Try to add the certificate variant too */
1490                 xasprintf(&cp, "%s-cert", filename);
1491                 public = key_load_public(cp, NULL);
1492                 debug("identity file %s type %d", cp,
1493                     public ? public->type : -1);
1494                 if (public == NULL) {
1495                         xfree(cp);
1496                         continue;
1497                 }
1498                 if (!key_is_cert(public)) {
1499                         debug("%s: key %s type %s is not a certificate",
1500                             __func__, cp, key_type(public));
1501                         key_free(public);
1502                         xfree(cp);
1503                         continue;
1504                 }
1505                 identity_keys[n_ids] = public;
1506                 /* point to the original path, most likely the private key */
1507                 identity_files[n_ids] = xstrdup(filename);
1508                 n_ids++;
1509         }
1510         options.num_identity_files = n_ids;
1511         memcpy(options.identity_files, identity_files, sizeof(identity_files));
1512         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
1513
1514         bzero(pwname, strlen(pwname));
1515         xfree(pwname);
1516         bzero(pwdir, strlen(pwdir));
1517         xfree(pwdir);
1518 }