crypto/openssh/ssh.c

   1 /* $OpenBSD: ssh.c,v 1.401 2014/02/26 20:18:37 djm Exp $ */
   2 /* $FreeBSD$ */
   3 /*
   4  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   5  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   6  *                    All rights reserved
   7  * Ssh client program.  This program can be used to log into a remote machine.
   8  * The software supports strong authentication, encryption, and forwarding
   9  * of X11, TCP/IP, and authentication connections.
  10  *
  11  * As far as I am concerned, the code I have written for this software
  12  * can be used freely for any purpose.  Any derived versions of this
  13  * software must be clearly marked as such, and if the derived work is
  14  * incompatible with the protocol description in the RFC file, it must be
  15  * called by a name other than "ssh" or "Secure Shell".
  16  *
  17  * Copyright (c) 1999 Niels Provos.  All rights reserved.
  18  * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl.  All rights reserved.
  19  *
  20  * Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
  21  * in Canada (German citizen).
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the above copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  *
  32  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  33  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  34  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  35  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  36  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  37  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  38  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  39  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  40  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  41  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  42  */
  43
  44 #include "includes.h"
  45 __RCSID("$FreeBSD$");
  46
  47 #include <sys/types.h>
  48 #ifdef HAVE_SYS_STAT_H
  49 # include <sys/stat.h>
  50 #endif
  51 #include <sys/resource.h>
  52 #include <sys/ioctl.h>
  53 #include <sys/param.h>
  54 #include <sys/socket.h>
  55 #include <sys/wait.h>
  56
  57 #include <ctype.h>
  58 #include <errno.h>
  59 #include <fcntl.h>
  60 #include <netdb.h>
  61 #ifdef HAVE_PATHS_H
  62 #include <paths.h>
  63 #endif
  64 #include <pwd.h>
  65 #include <signal.h>
  66 #include <stdarg.h>
  67 #include <stddef.h>
  68 #include <stdio.h>
  69 #include <stdlib.h>
  70 #include <string.h>
  71 #include <unistd.h>
  72
  73 #include <netinet/in.h>
  74 #include <arpa/inet.h>
  75
  76 #include <openssl/evp.h>
  77 #include <openssl/err.h>
  78 #include "openbsd-compat/openssl-compat.h"
  79 #include "openbsd-compat/sys-queue.h"
  80
  81 #include "xmalloc.h"
  82 #include "ssh.h"
  83 #include "ssh1.h"
  84 #include "ssh2.h"
  85 #include "canohost.h"
  86 #include "compat.h"
  87 #include "cipher.h"
  88 #include "packet.h"
  89 #include "buffer.h"
  90 #include "channels.h"
  91 #include "key.h"
  92 #include "authfd.h"
  93 #include "authfile.h"
  94 #include "pathnames.h"
  95 #include "dispatch.h"
  96 #include "clientloop.h"
  97 #include "log.h"
  98 #include "readconf.h"
  99 #include "sshconnect.h"
 100 #include "misc.h"
 101 #include "kex.h"
 102 #include "mac.h"
 103 #include "sshpty.h"
 104 #include "match.h"
 105 #include "msg.h"
 106 #include "uidswap.h"
 107 #include "roaming.h"
 108 #include "version.h"
 109
 110 #ifdef ENABLE_PKCS11
 111 #include "ssh-pkcs11.h"
 112 #endif
 113
 114 extern char *__progname;
 115
 116 /* Saves a copy of argv for setproctitle emulation */
 117 #ifndef HAVE_SETPROCTITLE
 118 static char **saved_av;
 119 #endif
 120
 121 /* Flag indicating whether debug mode is on.  May be set on the command line. */
 122 int debug_flag = 0;
 123
 124 /* Flag indicating whether a tty should be requested */
 125 int tty_flag = 0;
 126
 127 /* don't exec a shell */
 128 int no_shell_flag = 0;
 129
 130 /*
 131  * Flag indicating that nothing should be read from stdin.  This can be set
 132  * on the command line.
 133  */
 134 int stdin_null_flag = 0;
 135
 136 /*
 137  * Flag indicating that the current process should be backgrounded and
 138  * a new slave launched in the foreground for ControlPersist.
 139  */
 140 int need_controlpersist_detach = 0;
 141
 142 /* Copies of flags for ControlPersist foreground slave */
 143 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
 144
 145 /*
 146  * Flag indicating that ssh should fork after authentication.  This is useful
 147  * so that the passphrase can be entered manually, and then ssh goes to the
 148  * background.
 149  */
 150 int fork_after_authentication_flag = 0;
 151
 152 /* forward stdio to remote host and port */
 153 char *stdio_forward_host = NULL;
 154 int stdio_forward_port = 0;
 155
 156 /*
 157  * General data structure for command line options and options configurable
 158  * in configuration files.  See readconf.h.
 159  */
 160 Options options;
 161
 162 /* optional user configfile */
 163 char *config = NULL;
 164
 165 /*
 166  * Name of the host we are connecting to.  This is the name given on the
 167  * command line, or the HostName specified for the user-supplied name in a
 168  * configuration file.
 169  */
 170 char *host;
 171
 172 /* socket address the host resolves to */
 173 struct sockaddr_storage hostaddr;
 174
 175 /* Private host keys. */
 176 Sensitive sensitive_data;
 177
 178 /* Original real UID. */
 179 uid_t original_real_uid;
 180 uid_t original_effective_uid;
 181
 182 /* command to be executed */
 183 Buffer command;
 184
 185 /* Should we execute a command or invoke a subsystem? */
 186 int subsystem_flag = 0;
 187
 188 /* # of replies received for global requests */
 189 static int remote_forward_confirms_received = 0;
 190
 191 /* mux.c */
 192 extern int muxserver_sock;
 193 extern u_int muxclient_command;
 194
 195 /* Prints a help message to the user.  This function never returns. */
 196
 197 static void
 198 usage(void)
 199 {
 200         fprintf(stderr,
 201 "usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n"
 202 "           [-D [bind_address:]port] [-E log_file] [-e escape_char]\n"
 203 "           [-F configfile] [-I pkcs11] [-i identity_file]\n"
 204 "           [-L [bind_address:]port:host:hostport] [-l login_name] [-m mac_spec]\n"
 205 "           [-O ctl_cmd] [-o option] [-p port]\n"
 206 "           [-Q cipher | cipher-auth | mac | kex | key]\n"
 207 "           [-R [bind_address:]port:host:hostport] [-S ctl_path] [-W host:port]\n"
 208 "           [-w local_tun[:remote_tun]] [user@]hostname [command]\n"
 209         );
 210         exit(255);
 211 }
 212
 213 static int ssh_session(void);
 214 static int ssh_session2(void);
 215 static void load_public_identity_files(void);
 216 static void main_sigchld_handler(int);
 217
 218 /* from muxclient.c */
 219 void muxclient(const char *);
 220 void muxserver_listen(void);
 221
 222 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */
 223 static void
 224 tilde_expand_paths(char **paths, u_int num_paths)
 225 {
 226         u_int i;
 227         char *cp;
 228
 229         for (i = 0; i < num_paths; i++) {
 230                 cp = tilde_expand_filename(paths[i], original_real_uid);
 231                 free(paths[i]);
 232                 paths[i] = cp;
 233         }
 234 }
 235
 236 /*
 237  * Attempt to resolve a host name / port to a set of addresses and
 238  * optionally return any CNAMEs encountered along the way.
 239  * Returns NULL on failure.
 240  * NB. this function must operate with a options having undefined members.
 241  */
 242 static struct addrinfo *
 243 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen)
 244 {
 245         char strport[NI_MAXSERV];
 246         struct addrinfo hints, *res;
 247         int gaierr, loglevel = SYSLOG_LEVEL_DEBUG1;
 248
 249         if (port <= 0)
 250                 port = default_ssh_port();
 251
 252         snprintf(strport, sizeof strport, "%u", port);
 253         memset(&hints, 0, sizeof(hints));
 254         hints.ai_family = options.address_family == -1 ?
 255             AF_UNSPEC : options.address_family;
 256         hints.ai_socktype = SOCK_STREAM;
 257         if (cname != NULL)
 258                 hints.ai_flags = AI_CANONNAME;
 259         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 260                 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA))
 261                         loglevel = SYSLOG_LEVEL_ERROR;
 262                 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s",
 263                     __progname, name, ssh_gai_strerror(gaierr));
 264                 return NULL;
 265         }
 266         if (cname != NULL && res->ai_canonname != NULL) {
 267                 if (strlcpy(cname, res->ai_canonname, clen) >= clen) {
 268                         error("%s: host \"%s\" cname \"%s\" too long (max %lu)",
 269                             __func__, name,  res->ai_canonname, (u_long)clen);
 270                         if (clen > 0)
 271                                 *cname = '\0';
 272                 }
 273         }
 274         return res;
 275 }
 276
 277 /*
 278  * Check whether the cname is a permitted replacement for the hostname
 279  * and perform the replacement if it is.
 280  * NB. this function must operate with a options having undefined members.
 281  */
 282 static int
 283 check_follow_cname(char **namep, const char *cname)
 284 {
 285         int i;
 286         struct allowed_cname *rule;
 287
 288         if (*cname == '\0' || options.num_permitted_cnames == 0 ||
 289             strcmp(*namep, cname) == 0)
 290                 return 0;
 291         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 292                 return 0;
 293         /*
 294          * Don't attempt to canonicalize names that will be interpreted by
 295          * a proxy unless the user specifically requests so.
 296          */
 297         if (!option_clear_or_none(options.proxy_command) &&
 298             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 299                 return 0;
 300         debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname);
 301         for (i = 0; i < options.num_permitted_cnames; i++) {
 302                 rule = options.permitted_cnames + i;
 303                 if (match_pattern_list(*namep, rule->source_list,
 304                     strlen(rule->source_list), 1) != 1 ||
 305                     match_pattern_list(cname, rule->target_list,
 306                     strlen(rule->target_list), 1) != 1)
 307                         continue;
 308                 verbose("Canonicalized DNS aliased hostname "
 309                     "\"%s\" => \"%s\"", *namep, cname);
 310                 free(*namep);
 311                 *namep = xstrdup(cname);
 312                 return 1;
 313         }
 314         return 0;
 315 }
 316
 317 /*
 318  * Attempt to resolve the supplied hostname after applying the user's
 319  * canonicalization rules. Returns the address list for the host or NULL
 320  * if no name was found after canonicalization.
 321  * NB. this function must operate with a options having undefined members.
 322  */
 323 static struct addrinfo *
 324 resolve_canonicalize(char **hostp, int port)
 325 {
 326         int i, ndots;
 327         char *cp, *fullhost, cname_target[NI_MAXHOST];
 328         struct addrinfo *addrs;
 329
 330         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 331                 return NULL;
 332
 333         /*
 334          * Don't attempt to canonicalize names that will be interpreted by
 335          * a proxy unless the user specifically requests so.
 336          */
 337         if (!option_clear_or_none(options.proxy_command) &&
 338             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 339                 return NULL;
 340
 341         /* Don't apply canonicalization to sufficiently-qualified hostnames */
 342         ndots = 0;
 343         for (cp = *hostp; *cp != '\0'; cp++) {
 344                 if (*cp == '.')
 345                         ndots++;
 346         }
 347         if (ndots > options.canonicalize_max_dots) {
 348                 debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)",
 349                     __func__, *hostp, options.canonicalize_max_dots);
 350                 return NULL;
 351         }
 352         /* Attempt each supplied suffix */
 353         for (i = 0; i < options.num_canonical_domains; i++) {
 354                 *cname_target = '\0';
 355                 xasprintf(&fullhost, "%s.%s.", *hostp,
 356                     options.canonical_domains[i]);
 357                 debug3("%s: attempting \"%s\" => \"%s\"", __func__,
 358                     *hostp, fullhost);
 359                 if ((addrs = resolve_host(fullhost, port, 0,
 360                     cname_target, sizeof(cname_target))) == NULL) {
 361                         free(fullhost);
 362                         continue;
 363                 }
 364                 /* Remove trailing '.' */
 365                 fullhost[strlen(fullhost) - 1] = '\0';
 366                 /* Follow CNAME if requested */
 367                 if (!check_follow_cname(&fullhost, cname_target)) {
 368                         debug("Canonicalized hostname \"%s\" => \"%s\"",
 369                             *hostp, fullhost);
 370                 }
 371                 free(*hostp);
 372                 *hostp = fullhost;
 373                 return addrs;
 374         }
 375         if (!options.canonicalize_fallback_local)
 376                 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
 377         debug2("%s: host %s not found in any suffix", __func__, *hostp);
 378         return NULL;
 379 }
 380
 381 /*
 382  * Read per-user configuration file.  Ignore the system wide config
 383  * file if the user specifies a config file on the command line.
 384  */
 385 static void
 386 process_config_files(struct passwd *pw)
 387 {
 388         char buf[MAXPATHLEN];
 389         int r;
 390
 391         if (config != NULL) {
 392                 if (strcasecmp(config, "none") != 0 &&
 393                     !read_config_file(config, pw, host, &options,
 394                     SSHCONF_USERCONF))
 395                         fatal("Can't open user config file %.100s: "
 396                             "%.100s", config, strerror(errno));
 397         } else {
 398                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
 399                     _PATH_SSH_USER_CONFFILE);
 400                 if (r > 0 && (size_t)r < sizeof(buf))
 401                         (void)read_config_file(buf, pw, host, &options,
 402                              SSHCONF_CHECKPERM|SSHCONF_USERCONF);
 403
 404                 /* Read systemwide configuration file after user config. */
 405                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw, host,
 406                     &options, 0);
 407         }
 408 }
 409
 410 /*
 411  * Main program for the ssh client.
 412  */
 413 int
 414 main(int ac, char **av)
 415 {
 416         int i, r, opt, exit_status, use_syslog;
 417         char *p, *cp, *line, *argv0, buf[MAXPATHLEN], *host_arg, *logfile;
 418         char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
 419         char cname[NI_MAXHOST];
 420         struct stat st;
 421         struct passwd *pw;
 422         int timeout_ms;
 423         extern int optind, optreset;
 424         extern char *optarg;
 425         Forward fwd;
 426         struct addrinfo *addrs = NULL;
 427
 428         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 429         sanitise_stdfd();
 430
 431         __progname = ssh_get_progname(av[0]);
 432
 433 #ifndef HAVE_SETPROCTITLE
 434         /* Prepare for later setproctitle emulation */
 435         /* Save argv so it isn't clobbered by setproctitle() emulation */
 436         saved_av = xcalloc(ac + 1, sizeof(*saved_av));
 437         for (i = 0; i < ac; i++)
 438                 saved_av[i] = xstrdup(av[i]);
 439         saved_av[i] = NULL;
 440         compat_init_setproctitle(ac, av);
 441         av = saved_av;
 442 #endif
 443
 444         /*
 445          * Discard other fds that are hanging around. These can cause problem
 446          * with backgrounded ssh processes started by ControlPersist.
 447          */
 448         closefrom(STDERR_FILENO + 1);
 449
 450         /*
 451          * Save the original real uid.  It will be needed later (uid-swapping
 452          * may clobber the real uid).
 453          */
 454         original_real_uid = getuid();
 455         original_effective_uid = geteuid();
 456
 457         /*
 458          * Use uid-swapping to give up root privileges for the duration of
 459          * option processing.  We will re-instantiate the rights when we are
 460          * ready to create the privileged port, and will permanently drop
 461          * them when the port has been created (actually, when the connection
 462          * has been made, as we may need to create the port several times).
 463          */
 464         PRIV_END;
 465
 466 #ifdef HAVE_SETRLIMIT
 467         /* If we are installed setuid root be careful to not drop core. */
 468         if (original_real_uid != original_effective_uid) {
 469                 struct rlimit rlim;
 470                 rlim.rlim_cur = rlim.rlim_max = 0;
 471                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 472                         fatal("setrlimit failed: %.100s", strerror(errno));
 473         }
 474 #endif
 475         /* Get user data. */
 476         pw = getpwuid(original_real_uid);
 477         if (!pw) {
 478                 logit("No user exists for uid %lu", (u_long)original_real_uid);
 479                 exit(255);
 480         }
 481         /* Take a copy of the returned structure. */
 482         pw = pwcopy(pw);
 483
 484         /*
 485          * Set our umask to something reasonable, as some files are created
 486          * with the default umask.  This will make them world-readable but
 487          * writable only by the owner, which is ok for all files for which we
 488          * don't set the modes explicitly.
 489          */
 490         umask(022);
 491
 492         /*
 493          * Initialize option structure to indicate that no values have been
 494          * set.
 495          */
 496         initialize_options(&options);
 497
 498         /* Parse command-line arguments. */
 499         host = NULL;
 500         use_syslog = 0;
 501         logfile = NULL;
 502         argv0 = av[0];
 503
 504  again:
 505         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
 506             "ACD:E:F:I:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
 507                 switch (opt) {
 508                 case '1':
 509                         options.protocol = SSH_PROTO_1;
 510                         break;
 511                 case '2':
 512                         options.protocol = SSH_PROTO_2;
 513                         break;
 514                 case '4':
 515                         options.address_family = AF_INET;
 516                         break;
 517                 case '6':
 518                         options.address_family = AF_INET6;
 519                         break;
 520                 case 'n':
 521                         stdin_null_flag = 1;
 522                         break;
 523                 case 'f':
 524                         fork_after_authentication_flag = 1;
 525                         stdin_null_flag = 1;
 526                         break;
 527                 case 'x':
 528                         options.forward_x11 = 0;
 529                         break;
 530                 case 'X':
 531                         options.forward_x11 = 1;
 532                         break;
 533                 case 'y':
 534                         use_syslog = 1;
 535                         break;
 536                 case 'E':
 537                         logfile = xstrdup(optarg);
 538                         break;
 539                 case 'Y':
 540                         options.forward_x11 = 1;
 541                         options.forward_x11_trusted = 1;
 542                         break;
 543                 case 'g':
 544                         options.gateway_ports = 1;
 545                         break;
 546                 case 'O':
 547                         if (stdio_forward_host != NULL)
 548                                 fatal("Cannot specify multiplexing "
 549                                     "command with -W");
 550                         else if (muxclient_command != 0)
 551                                 fatal("Multiplexing command already specified");
 552                         if (strcmp(optarg, "check") == 0)
 553                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
 554                         else if (strcmp(optarg, "forward") == 0)
 555                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
 556                         else if (strcmp(optarg, "exit") == 0)
 557                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
 558                         else if (strcmp(optarg, "stop") == 0)
 559                                 muxclient_command = SSHMUX_COMMAND_STOP;
 560                         else if (strcmp(optarg, "cancel") == 0)
 561                                 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
 562                         else
 563                                 fatal("Invalid multiplex command.");
 564                         break;
 565                 case 'P':       /* deprecated */
 566                         options.use_privileged_port = 0;
 567                         break;
 568                 case 'Q':
 569                         cp = NULL;
 570                         if (strcmp(optarg, "cipher") == 0)
 571                                 cp = cipher_alg_list('\n', 0);
 572                         else if (strcmp(optarg, "cipher-auth") == 0)
 573                                 cp = cipher_alg_list('\n', 1);
 574                         else if (strcmp(optarg, "mac") == 0)
 575                                 cp = mac_alg_list('\n');
 576                         else if (strcmp(optarg, "kex") == 0)
 577                                 cp = kex_alg_list('\n');
 578                         else if (strcmp(optarg, "key") == 0)
 579                                 cp = key_alg_list(0, 0);
 580                         else if (strcmp(optarg, "key-cert") == 0)
 581                                 cp = key_alg_list(1, 0);
 582                         else if (strcmp(optarg, "key-plain") == 0)
 583                                 cp = key_alg_list(0, 1);
 584                         if (cp == NULL)
 585                                 fatal("Unsupported query \"%s\"", optarg);
 586                         printf("%s\n", cp);
 587                         free(cp);
 588                         exit(0);
 589                         break;
 590                 case 'a':
 591                         options.forward_agent = 0;
 592                         break;
 593                 case 'A':
 594                         options.forward_agent = 1;
 595                         break;
 596                 case 'k':
 597                         options.gss_deleg_creds = 0;
 598                         break;
 599                 case 'K':
 600                         options.gss_authentication = 1;
 601                         options.gss_deleg_creds = 1;
 602                         break;
 603                 case 'i':
 604                         if (stat(optarg, &st) < 0) {
 605                                 fprintf(stderr, "Warning: Identity file %s "
 606                                     "not accessible: %s.\n", optarg,
 607                                     strerror(errno));
 608                                 break;
 609                         }
 610                         add_identity_file(&options, NULL, optarg, 1);
 611                         break;
 612                 case 'I':
 613 #ifdef ENABLE_PKCS11
 614                         options.pkcs11_provider = xstrdup(optarg);
 615 #else
 616                         fprintf(stderr, "no support for PKCS#11.\n");
 617 #endif
 618                         break;
 619                 case 't':
 620                         if (options.request_tty == REQUEST_TTY_YES)
 621                                 options.request_tty = REQUEST_TTY_FORCE;
 622                         else
 623                                 options.request_tty = REQUEST_TTY_YES;
 624                         break;
 625                 case 'v':
 626                         if (debug_flag == 0) {
 627                                 debug_flag = 1;
 628                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 629                         } else {
 630                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
 631                                         options.log_level++;
 632                         }
 633                         break;
 634                 case 'V':
 635                         if (options.version_addendum &&
 636                             *options.version_addendum != '\0')
 637                                 fprintf(stderr, "%s%s %s, %s\n", SSH_RELEASE,
 638                                     options.hpn_disabled ? "" : SSH_VERSION_HPN,
 639                                     options.version_addendum,
 640                                     SSLeay_version(SSLEAY_VERSION));
 641                         else
 642                                 fprintf(stderr, "%s%s, %s\n", SSH_RELEASE,
 643                                     options.hpn_disabled ? "" : SSH_VERSION_HPN,
 644                                     SSLeay_version(SSLEAY_VERSION));
 645                         if (opt == 'V')
 646                                 exit(0);
 647                         break;
 648                 case 'w':
 649                         if (options.tun_open == -1)
 650                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 651                         options.tun_local = a2tun(optarg, &options.tun_remote);
 652                         if (options.tun_local == SSH_TUNID_ERR) {
 653                                 fprintf(stderr,
 654                                     "Bad tun device '%s'\n", optarg);
 655                                 exit(255);
 656                         }
 657                         break;
 658                 case 'W':
 659                         if (stdio_forward_host != NULL)
 660                                 fatal("stdio forward already specified");
 661                         if (muxclient_command != 0)
 662                                 fatal("Cannot specify stdio forward with -O");
 663                         if (parse_forward(&fwd, optarg, 1, 0)) {
 664                                 stdio_forward_host = fwd.listen_host;
 665                                 stdio_forward_port = fwd.listen_port;
 666                                 free(fwd.connect_host);
 667                         } else {
 668                                 fprintf(stderr,
 669                                     "Bad stdio forwarding specification '%s'\n",
 670                                     optarg);
 671                                 exit(255);
 672                         }
 673                         options.request_tty = REQUEST_TTY_NO;
 674                         no_shell_flag = 1;
 675                         options.clear_forwardings = 1;
 676                         options.exit_on_forward_failure = 1;
 677                         break;
 678                 case 'q':
 679                         options.log_level = SYSLOG_LEVEL_QUIET;
 680                         break;
 681                 case 'e':
 682                         if (optarg[0] == '^' && optarg[2] == 0 &&
 683                             (u_char) optarg[1] >= 64 &&
 684                             (u_char) optarg[1] < 128)
 685                                 options.escape_char = (u_char) optarg[1] & 31;
 686                         else if (strlen(optarg) == 1)
 687                                 options.escape_char = (u_char) optarg[0];
 688                         else if (strcmp(optarg, "none") == 0)
 689                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 690                         else {
 691                                 fprintf(stderr, "Bad escape character '%s'.\n",
 692                                     optarg);
 693                                 exit(255);
 694                         }
 695                         break;
 696                 case 'c':
 697                         if (ciphers_valid(optarg)) {
 698                                 /* SSH2 only */
 699                                 options.ciphers = xstrdup(optarg);
 700                                 options.cipher = SSH_CIPHER_INVALID;
 701                         } else {
 702                                 /* SSH1 only */
 703                                 options.cipher = cipher_number(optarg);
 704                                 if (options.cipher == -1) {
 705                                         fprintf(stderr,
 706                                             "Unknown cipher type '%s'\n",
 707                                             optarg);
 708                                         exit(255);
 709                                 }
 710                                 if (options.cipher == SSH_CIPHER_3DES)
 711                                         options.ciphers = "3des-cbc";
 712                                 else if (options.cipher == SSH_CIPHER_BLOWFISH)
 713                                         options.ciphers = "blowfish-cbc";
 714                                 else
 715                                         options.ciphers = (char *)-1;
 716                         }
 717                         break;
 718                 case 'm':
 719                         if (mac_valid(optarg))
 720                                 options.macs = xstrdup(optarg);
 721                         else {
 722                                 fprintf(stderr, "Unknown mac type '%s'\n",
 723                                     optarg);
 724                                 exit(255);
 725                         }
 726                         break;
 727                 case 'M':
 728                         if (options.control_master == SSHCTL_MASTER_YES)
 729                                 options.control_master = SSHCTL_MASTER_ASK;
 730                         else
 731                                 options.control_master = SSHCTL_MASTER_YES;
 732                         break;
 733                 case 'p':
 734                         options.port = a2port(optarg);
 735                         if (options.port <= 0) {
 736                                 fprintf(stderr, "Bad port '%s'\n", optarg);
 737                                 exit(255);
 738                         }
 739                         break;
 740                 case 'l':
 741                         options.user = optarg;
 742                         break;
 743
 744                 case 'L':
 745                         if (parse_forward(&fwd, optarg, 0, 0))
 746                                 add_local_forward(&options, &fwd);
 747                         else {
 748                                 fprintf(stderr,
 749                                     "Bad local forwarding specification '%s'\n",
 750                                     optarg);
 751                                 exit(255);
 752                         }
 753                         break;
 754
 755                 case 'R':
 756                         if (parse_forward(&fwd, optarg, 0, 1)) {
 757                                 add_remote_forward(&options, &fwd);
 758                         } else {
 759                                 fprintf(stderr,
 760                                     "Bad remote forwarding specification "
 761                                     "'%s'\n", optarg);
 762                                 exit(255);
 763                         }
 764                         break;
 765
 766                 case 'D':
 767                         if (parse_forward(&fwd, optarg, 1, 0)) {
 768                                 add_local_forward(&options, &fwd);
 769                         } else {
 770                                 fprintf(stderr,
 771                                     "Bad dynamic forwarding specification "
 772                                     "'%s'\n", optarg);
 773                                 exit(255);
 774                         }
 775                         break;
 776
 777                 case 'C':
 778                         options.compression = 1;
 779                         break;
 780                 case 'N':
 781                         no_shell_flag = 1;
 782                         options.request_tty = REQUEST_TTY_NO;
 783                         break;
 784                 case 'T':
 785                         options.request_tty = REQUEST_TTY_NO;
 786 #ifdef  NONE_CIPHER_ENABLED
 787                         /*
 788                          * Ensure that the user does not try to backdoor a
 789                          * NONE cipher switch on an interactive session by
 790                          * explicitly disabling it if the user asks for a
 791                          * session without a tty.
 792                          */
 793                         options.none_switch = 0;
 794 #endif
 795                         break;
 796                 case 'o':
 797                         line = xstrdup(optarg);
 798                         if (process_config_line(&options, pw, host ? host : "",
 799                             line, "command-line", 0, NULL, SSHCONF_USERCONF)
 800                             != 0)
 801                                 exit(255);
 802                         free(line);
 803                         break;
 804                 case 's':
 805                         subsystem_flag = 1;
 806                         break;
 807                 case 'S':
 808                         if (options.control_path != NULL)
 809                                 free(options.control_path);
 810                         options.control_path = xstrdup(optarg);
 811                         break;
 812                 case 'b':
 813                         options.bind_address = optarg;
 814                         break;
 815                 case 'F':
 816                         config = optarg;
 817                         break;
 818                 default:
 819                         usage();
 820                 }
 821         }
 822
 823         ac -= optind;
 824         av += optind;
 825
 826         if (ac > 0 && !host) {
 827                 if (strrchr(*av, '@')) {
 828                         p = xstrdup(*av);
 829                         cp = strrchr(p, '@');
 830                         if (cp == NULL || cp == p)
 831                                 usage();
 832                         options.user = p;
 833                         *cp = '\0';
 834                         host = xstrdup(++cp);
 835                 } else
 836                         host = xstrdup(*av);
 837                 if (ac > 1) {
 838                         optind = optreset = 1;
 839                         goto again;
 840                 }
 841                 ac--, av++;
 842         }
 843
 844         /* Check that we got a host name. */
 845         if (!host)
 846                 usage();
 847
 848         host_arg = xstrdup(host);
 849
 850         OpenSSL_add_all_algorithms();
 851         ERR_load_crypto_strings();
 852
 853         /* Initialize the command to execute on remote host. */
 854         buffer_init(&command);
 855
 856         /*
 857          * Save the command to execute on the remote host in a buffer. There
 858          * is no limit on the length of the command, except by the maximum
 859          * packet size.  Also sets the tty flag if there is no command.
 860          */
 861         if (!ac) {
 862                 /* No command specified - execute shell on a tty. */
 863                 if (subsystem_flag) {
 864                         fprintf(stderr,
 865                             "You must specify a subsystem to invoke.\n");
 866                         usage();
 867                 }
 868         } else {
 869                 /* A command has been specified.  Store it into the buffer. */
 870                 for (i = 0; i < ac; i++) {
 871                         if (i)
 872                                 buffer_append(&command, " ", 1);
 873                         buffer_append(&command, av[i], strlen(av[i]));
 874                 }
 875         }
 876
 877         /* Cannot fork to background if no command. */
 878         if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
 879             !no_shell_flag)
 880                 fatal("Cannot fork into background without a command "
 881                     "to execute.");
 882
 883         /*
 884          * Initialize "log" output.  Since we are the client all output
 885          * goes to stderr unless otherwise specified by -y or -E.
 886          */
 887         if (use_syslog && logfile != NULL)
 888                 fatal("Can't specify both -y and -E");
 889         if (logfile != NULL) {
 890                 log_redirect_stderr_to(logfile);
 891                 free(logfile);
 892         }
 893         log_init(argv0,
 894             options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
 895             SYSLOG_FACILITY_USER, !use_syslog);
 896
 897         if (debug_flag)
 898                 logit("%s, %s", SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
 899
 900         /* Parse the configuration files */
 901         process_config_files(pw);
 902
 903         /* Hostname canonicalisation needs a few options filled. */
 904         fill_default_options_for_canonicalization(&options);
 905
 906         /* If the user has replaced the hostname then take it into use now */
 907         if (options.hostname != NULL) {
 908                 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
 909                 cp = percent_expand(options.hostname,
 910                     "h", host, (char *)NULL);
 911                 free(host);
 912                 host = cp;
 913         }
 914
 915         /* If canonicalization requested then try to apply it */
 916         lowercase(host);
 917         if (options.canonicalize_hostname != SSH_CANONICALISE_NO)
 918                 addrs = resolve_canonicalize(&host, options.port);
 919
 920         /*
 921          * If CanonicalizePermittedCNAMEs have been specified but
 922          * other canonicalization did not happen (by not being requested
 923          * or by failing with fallback) then the hostname may still be changed
 924          * as a result of CNAME following.
 925          *
 926          * Try to resolve the bare hostname name using the system resolver's
 927          * usual search rules and then apply the CNAME follow rules.
 928          *
 929          * Skip the lookup if a ProxyCommand is being used unless the user
 930          * has specifically requested canonicalisation for this case via
 931          * CanonicalizeHostname=always
 932          */
 933         if (addrs == NULL && options.num_permitted_cnames != 0 &&
 934             (option_clear_or_none(options.proxy_command) ||
 935             options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
 936                 if ((addrs = resolve_host(host, options.port, 1,
 937                     cname, sizeof(cname))) == NULL)
 938                         cleanup_exit(255); /* resolve_host logs the error */
 939                 check_follow_cname(&host, cname);
 940         }
 941
 942         /*
 943          * If the target hostname has changed as a result of canonicalisation
 944          * then re-parse the configuration files as new stanzas may match.
 945          */
 946         if (strcasecmp(host_arg, host) != 0) {
 947                 debug("Hostname has changed; re-reading configuration");
 948                 process_config_files(pw);
 949         }
 950
 951         /* Fill configuration defaults. */
 952         fill_default_options(&options);
 953
 954         if (options.port == 0)
 955                 options.port = default_ssh_port();
 956         channel_set_af(options.address_family);
 957
 958         /* Tidy and check options */
 959         if (options.host_key_alias != NULL)
 960                 lowercase(options.host_key_alias);
 961         if (options.proxy_command != NULL &&
 962             strcmp(options.proxy_command, "-") == 0 &&
 963             options.proxy_use_fdpass)
 964                 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
 965 #ifndef HAVE_CYGWIN
 966         if (original_effective_uid != 0)
 967                 options.use_privileged_port = 0;
 968 #endif
 969
 970         /* reinit */
 971         log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
 972
 973         if (options.request_tty == REQUEST_TTY_YES ||
 974             options.request_tty == REQUEST_TTY_FORCE)
 975                 tty_flag = 1;
 976
 977         /* Allocate a tty by default if no command specified. */
 978         if (buffer_len(&command) == 0)
 979                 tty_flag = options.request_tty != REQUEST_TTY_NO;
 980
 981         /* Force no tty */
 982         if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0)
 983                 tty_flag = 0;
 984         /* Do not allocate a tty if stdin is not a tty. */
 985         if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
 986             options.request_tty != REQUEST_TTY_FORCE) {
 987                 if (tty_flag)
 988                         logit("Pseudo-terminal will not be allocated because "
 989                             "stdin is not a terminal.");
 990                 tty_flag = 0;
 991         }
 992
 993         seed_rng();
 994
 995         if (options.user == NULL)
 996                 options.user = xstrdup(pw->pw_name);
 997
 998         if (gethostname(thishost, sizeof(thishost)) == -1)
 999                 fatal("gethostname: %s", strerror(errno));
1000         strlcpy(shorthost, thishost, sizeof(shorthost));
1001         shorthost[strcspn(thishost, ".")] = '\0';
1002         snprintf(portstr, sizeof(portstr), "%d", options.port);
1003
1004         /* Find canonic host name. */
1005         if (strchr(host, '.') == 0) {
1006                 struct addrinfo hints;
1007                 struct addrinfo *ai = NULL;
1008                 int errgai;
1009                 memset(&hints, 0, sizeof(hints));
1010                 hints.ai_family = options.address_family;
1011                 hints.ai_flags = AI_CANONNAME;
1012                 hints.ai_socktype = SOCK_STREAM;
1013                 errgai = getaddrinfo(host, NULL, &hints, &ai);
1014                 if (errgai == 0) {
1015                         if (ai->ai_canonname != NULL)
1016                                 host = xstrdup(ai->ai_canonname);
1017                         freeaddrinfo(ai);
1018                 }
1019         }
1020
1021         if (options.local_command != NULL) {
1022                 debug3("expanding LocalCommand: %s", options.local_command);
1023                 cp = options.local_command;
1024                 options.local_command = percent_expand(cp, "d", pw->pw_dir,
1025                     "h", host, "l", thishost, "n", host_arg, "r", options.user,
1026                     "p", portstr, "u", pw->pw_name, "L", shorthost,
1027                     (char *)NULL);
1028                 debug3("expanded LocalCommand: %s", options.local_command);
1029                 free(cp);
1030         }
1031
1032         if (options.control_path != NULL) {
1033                 cp = tilde_expand_filename(options.control_path,
1034                     original_real_uid);
1035                 free(options.control_path);
1036                 options.control_path = percent_expand(cp, "h", host,
1037                     "l", thishost, "n", host_arg, "r", options.user,
1038                     "p", portstr, "u", pw->pw_name, "L", shorthost,
1039                     (char *)NULL);
1040                 free(cp);
1041         }
1042         if (muxclient_command != 0 && options.control_path == NULL)
1043                 fatal("No ControlPath specified for \"-O\" command");
1044         if (options.control_path != NULL)
1045                 muxclient(options.control_path);
1046
1047         /*
1048          * If hostname canonicalisation was not enabled, then we may not
1049          * have yet resolved the hostname. Do so now.
1050          */
1051         if (addrs == NULL && options.proxy_command == NULL) {
1052                 if ((addrs = resolve_host(host, options.port, 1,
1053                     cname, sizeof(cname))) == NULL)
1054                         cleanup_exit(255); /* resolve_host logs the error */
1055         }
1056
1057         timeout_ms = options.connection_timeout * 1000;
1058
1059         /* Open a connection to the remote host. */
1060         if (ssh_connect(host, addrs, &hostaddr, options.port,
1061             options.address_family, options.connection_attempts,
1062             &timeout_ms, options.tcp_keep_alive,
1063             options.use_privileged_port) != 0)
1064                 exit(255);
1065
1066         if (addrs != NULL)
1067                 freeaddrinfo(addrs);
1068
1069         packet_set_timeout(options.server_alive_interval,
1070             options.server_alive_count_max);
1071
1072         if (timeout_ms > 0)
1073                 debug3("timeout: %d ms remain after connect", timeout_ms);
1074
1075         /*
1076          * If we successfully made the connection, load the host private key
1077          * in case we will need it later for combined rsa-rhosts
1078          * authentication. This must be done before releasing extra
1079          * privileges, because the file is only readable by root.
1080          * If we cannot access the private keys, load the public keys
1081          * instead and try to execute the ssh-keysign helper instead.
1082          */
1083         sensitive_data.nkeys = 0;
1084         sensitive_data.keys = NULL;
1085         sensitive_data.external_keysign = 0;
1086         if (options.rhosts_rsa_authentication ||
1087             options.hostbased_authentication) {
1088                 sensitive_data.nkeys = 9;
1089                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1090                     sizeof(Key));
1091                 for (i = 0; i < sensitive_data.nkeys; i++)
1092                         sensitive_data.keys[i] = NULL;
1093
1094                 PRIV_START;
1095                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
1096                     _PATH_HOST_KEY_FILE, "", NULL, NULL);
1097                 sensitive_data.keys[1] = key_load_private_cert(KEY_DSA,
1098                     _PATH_HOST_DSA_KEY_FILE, "", NULL);
1099 #ifdef OPENSSL_HAS_ECC
1100                 sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA,
1101                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL);
1102 #endif
1103                 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
1104                     _PATH_HOST_RSA_KEY_FILE, "", NULL);
1105                 sensitive_data.keys[4] = key_load_private_cert(KEY_ED25519,
1106                     _PATH_HOST_ED25519_KEY_FILE, "", NULL);
1107                 sensitive_data.keys[5] = key_load_private_type(KEY_DSA,
1108                     _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
1109 #ifdef OPENSSL_HAS_ECC
1110                 sensitive_data.keys[6] = key_load_private_type(KEY_ECDSA,
1111                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL);
1112 #endif
1113                 sensitive_data.keys[7] = key_load_private_type(KEY_RSA,
1114                     _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
1115                 sensitive_data.keys[8] = key_load_private_type(KEY_ED25519,
1116                     _PATH_HOST_ED25519_KEY_FILE, "", NULL, NULL);
1117                 PRIV_END;
1118
1119                 if (options.hostbased_authentication == 1 &&
1120                     sensitive_data.keys[0] == NULL &&
1121                     sensitive_data.keys[5] == NULL &&
1122                     sensitive_data.keys[6] == NULL &&
1123                     sensitive_data.keys[7] == NULL &&
1124                     sensitive_data.keys[8] == NULL) {
1125                         sensitive_data.keys[1] = key_load_cert(
1126                             _PATH_HOST_DSA_KEY_FILE);
1127 #ifdef OPENSSL_HAS_ECC
1128                         sensitive_data.keys[2] = key_load_cert(
1129                             _PATH_HOST_ECDSA_KEY_FILE);
1130 #endif
1131                         sensitive_data.keys[3] = key_load_cert(
1132                             _PATH_HOST_RSA_KEY_FILE);
1133                         sensitive_data.keys[4] = key_load_cert(
1134                             _PATH_HOST_ED25519_KEY_FILE);
1135                         sensitive_data.keys[5] = key_load_public(
1136                             _PATH_HOST_DSA_KEY_FILE, NULL);
1137 #ifdef OPENSSL_HAS_ECC
1138                         sensitive_data.keys[6] = key_load_public(
1139                             _PATH_HOST_ECDSA_KEY_FILE, NULL);
1140 #endif
1141                         sensitive_data.keys[7] = key_load_public(
1142                             _PATH_HOST_RSA_KEY_FILE, NULL);
1143                         sensitive_data.keys[8] = key_load_public(
1144                             _PATH_HOST_ED25519_KEY_FILE, NULL);
1145                         sensitive_data.external_keysign = 1;
1146                 }
1147         }
1148         /*
1149          * Get rid of any extra privileges that we may have.  We will no
1150          * longer need them.  Also, extra privileges could make it very hard
1151          * to read identity files and other non-world-readable files from the
1152          * user's home directory if it happens to be on a NFS volume where
1153          * root is mapped to nobody.
1154          */
1155         if (original_effective_uid == 0) {
1156                 PRIV_START;
1157                 permanently_set_uid(pw);
1158         }
1159
1160         /*
1161          * Now that we are back to our own permissions, create ~/.ssh
1162          * directory if it doesn't already exist.
1163          */
1164         if (config == NULL) {
1165                 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
1166                     strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
1167                 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
1168 #ifdef WITH_SELINUX
1169                         ssh_selinux_setfscreatecon(buf);
1170 #endif
1171                         if (mkdir(buf, 0700) < 0)
1172                                 error("Could not create directory '%.200s'.",
1173                                     buf);
1174 #ifdef WITH_SELINUX
1175                         ssh_selinux_setfscreatecon(NULL);
1176 #endif
1177                 }
1178         }
1179         /* load options.identity_files */
1180         load_public_identity_files();
1181
1182         /* Expand ~ in known host file names. */
1183         tilde_expand_paths(options.system_hostfiles,
1184             options.num_system_hostfiles);
1185         tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1186
1187         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1188         signal(SIGCHLD, main_sigchld_handler);
1189
1190         /* Log into the remote system.  Never returns if the login fails. */
1191         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
1192             options.port, pw, timeout_ms);
1193
1194         if (packet_connection_is_on_socket()) {
1195                 verbose("Authenticated to %s ([%s]:%d).", host,
1196                     get_remote_ipaddr(), get_remote_port());
1197         } else {
1198                 verbose("Authenticated to %s (via proxy).", host);
1199         }
1200
1201         /* We no longer need the private host keys.  Clear them now. */
1202         if (sensitive_data.nkeys != 0) {
1203                 for (i = 0; i < sensitive_data.nkeys; i++) {
1204                         if (sensitive_data.keys[i] != NULL) {
1205                                 /* Destroys contents safely */
1206                                 debug3("clear hostkey %d", i);
1207                                 key_free(sensitive_data.keys[i]);
1208                                 sensitive_data.keys[i] = NULL;
1209                         }
1210                 }
1211                 free(sensitive_data.keys);
1212         }
1213         for (i = 0; i < options.num_identity_files; i++) {
1214                 free(options.identity_files[i]);
1215                 options.identity_files[i] = NULL;
1216                 if (options.identity_keys[i]) {
1217                         key_free(options.identity_keys[i]);
1218                         options.identity_keys[i] = NULL;
1219                 }
1220         }
1221
1222         exit_status = compat20 ? ssh_session2() : ssh_session();
1223         packet_close();
1224
1225         if (options.control_path != NULL && muxserver_sock != -1)
1226                 unlink(options.control_path);
1227
1228         /* Kill ProxyCommand if it is running. */
1229         ssh_kill_proxy_command();
1230
1231         return exit_status;
1232 }
1233
1234 static void
1235 control_persist_detach(void)
1236 {
1237         pid_t pid;
1238         int devnull;
1239
1240         debug("%s: backgrounding master process", __func__);
1241
1242         /*
1243          * master (current process) into the background, and make the
1244          * foreground process a client of the backgrounded master.
1245          */
1246         switch ((pid = fork())) {
1247         case -1:
1248                 fatal("%s: fork: %s", __func__, strerror(errno));
1249         case 0:
1250                 /* Child: master process continues mainloop */
1251                 break;
1252         default:
1253                 /* Parent: set up mux slave to connect to backgrounded master */
1254                 debug2("%s: background process is %ld", __func__, (long)pid);
1255                 stdin_null_flag = ostdin_null_flag;
1256                 options.request_tty = orequest_tty;
1257                 tty_flag = otty_flag;
1258                 close(muxserver_sock);
1259                 muxserver_sock = -1;
1260                 options.control_master = SSHCTL_MASTER_NO;
1261                 muxclient(options.control_path);
1262                 /* muxclient() doesn't return on success. */
1263                 fatal("Failed to connect to new control master");
1264         }
1265         if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1266                 error("%s: open(\"/dev/null\"): %s", __func__,
1267                     strerror(errno));
1268         } else {
1269                 if (dup2(devnull, STDIN_FILENO) == -1 ||
1270                     dup2(devnull, STDOUT_FILENO) == -1)
1271                         error("%s: dup2: %s", __func__, strerror(errno));
1272                 if (devnull > STDERR_FILENO)
1273                         close(devnull);
1274         }
1275         daemon(1, 1);
1276         setproctitle("%s [mux]", options.control_path);
1277 }
1278
1279 /* Do fork() after authentication. Used by "ssh -f" */
1280 static void
1281 fork_postauth(void)
1282 {
1283         if (need_controlpersist_detach)
1284                 control_persist_detach();
1285         debug("forking to background");
1286         fork_after_authentication_flag = 0;
1287         if (daemon(1, 1) < 0)
1288                 fatal("daemon() failed: %.200s", strerror(errno));
1289 }
1290
1291 /* Callback for remote forward global requests */
1292 static void
1293 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
1294 {
1295         Forward *rfwd = (Forward *)ctxt;
1296
1297         /* XXX verbose() on failure? */
1298         debug("remote forward %s for: listen %d, connect %s:%d",
1299             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1300             rfwd->listen_port, rfwd->connect_host, rfwd->connect_port);
1301         if (rfwd->listen_port == 0) {
1302                 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1303                         rfwd->allocated_port = packet_get_int();
1304                         logit("Allocated port %u for remote forward to %s:%d",
1305                             rfwd->allocated_port,
1306                             rfwd->connect_host, rfwd->connect_port);
1307                         channel_update_permitted_opens(rfwd->handle,
1308                             rfwd->allocated_port);
1309                 } else {
1310                         channel_update_permitted_opens(rfwd->handle, -1);
1311                 }
1312         }
1313
1314         if (type == SSH2_MSG_REQUEST_FAILURE) {
1315                 if (options.exit_on_forward_failure)
1316                         fatal("Error: remote port forwarding failed for "
1317                             "listen port %d", rfwd->listen_port);
1318                 else
1319                         logit("Warning: remote port forwarding failed for "
1320                             "listen port %d", rfwd->listen_port);
1321         }
1322         if (++remote_forward_confirms_received == options.num_remote_forwards) {
1323                 debug("All remote forwarding requests processed");
1324                 if (fork_after_authentication_flag)
1325                         fork_postauth();
1326         }
1327 }
1328
1329 static void
1330 client_cleanup_stdio_fwd(int id, void *arg)
1331 {
1332         debug("stdio forwarding: done");
1333         cleanup_exit(0);
1334 }
1335
1336 static void
1337 ssh_init_stdio_forwarding(void)
1338 {
1339         Channel *c;
1340         int in, out;
1341
1342         if (stdio_forward_host == NULL)
1343                 return;
1344         if (!compat20)
1345                 fatal("stdio forwarding require Protocol 2");
1346
1347         debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port);
1348
1349         if ((in = dup(STDIN_FILENO)) < 0 ||
1350             (out = dup(STDOUT_FILENO)) < 0)
1351                 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1352         if ((c = channel_connect_stdio_fwd(stdio_forward_host,
1353             stdio_forward_port, in, out)) == NULL)
1354                 fatal("%s: channel_connect_stdio_fwd failed", __func__);
1355         channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
1356 }
1357
1358 static void
1359 ssh_init_forwarding(void)
1360 {
1361         int success = 0;
1362         int i;
1363
1364         /* Initiate local TCP/IP port forwardings. */
1365         for (i = 0; i < options.num_local_forwards; i++) {
1366                 debug("Local connections to %.200s:%d forwarded to remote "
1367                     "address %.200s:%d",
1368                     (options.local_forwards[i].listen_host == NULL) ?
1369                     (options.gateway_ports ? "*" : "LOCALHOST") :
1370                     options.local_forwards[i].listen_host,
1371                     options.local_forwards[i].listen_port,
1372                     options.local_forwards[i].connect_host,
1373                     options.local_forwards[i].connect_port);
1374                 success += channel_setup_local_fwd_listener(
1375                     options.local_forwards[i].listen_host,
1376                     options.local_forwards[i].listen_port,
1377                     options.local_forwards[i].connect_host,
1378                     options.local_forwards[i].connect_port,
1379                     options.gateway_ports);
1380         }
1381         if (i > 0 && success != i && options.exit_on_forward_failure)
1382                 fatal("Could not request local forwarding.");
1383         if (i > 0 && success == 0)
1384                 error("Could not request local forwarding.");
1385
1386         /* Initiate remote TCP/IP port forwardings. */
1387         for (i = 0; i < options.num_remote_forwards; i++) {
1388                 debug("Remote connections from %.200s:%d forwarded to "
1389                     "local address %.200s:%d",
1390                     (options.remote_forwards[i].listen_host == NULL) ?
1391                     "LOCALHOST" : options.remote_forwards[i].listen_host,
1392                     options.remote_forwards[i].listen_port,
1393                     options.remote_forwards[i].connect_host,
1394                     options.remote_forwards[i].connect_port);
1395                 options.remote_forwards[i].handle =
1396                     channel_request_remote_forwarding(
1397                     options.remote_forwards[i].listen_host,
1398                     options.remote_forwards[i].listen_port,
1399                     options.remote_forwards[i].connect_host,
1400                     options.remote_forwards[i].connect_port);
1401                 if (options.remote_forwards[i].handle < 0) {
1402                         if (options.exit_on_forward_failure)
1403                                 fatal("Could not request remote forwarding.");
1404                         else
1405                                 logit("Warning: Could not request remote "
1406                                     "forwarding.");
1407                 } else {
1408                         client_register_global_confirm(ssh_confirm_remote_forward,
1409                             &options.remote_forwards[i]);
1410                 }
1411         }
1412
1413         /* Initiate tunnel forwarding. */
1414         if (options.tun_open != SSH_TUNMODE_NO) {
1415                 if (client_request_tun_fwd(options.tun_open,
1416                     options.tun_local, options.tun_remote) == -1) {
1417                         if (options.exit_on_forward_failure)
1418                                 fatal("Could not request tunnel forwarding.");
1419                         else
1420                                 error("Could not request tunnel forwarding.");
1421                 }
1422         }
1423 }
1424
1425 static void
1426 check_agent_present(void)
1427 {
1428         if (options.forward_agent) {
1429                 /* Clear agent forwarding if we don't have an agent. */
1430                 if (!ssh_agent_present())
1431                         options.forward_agent = 0;
1432         }
1433 }
1434
1435 static int
1436 ssh_session(void)
1437 {
1438         int type;
1439         int interactive = 0;
1440         int have_tty = 0;
1441         struct winsize ws;
1442         char *cp;
1443         const char *display;
1444
1445         /* Enable compression if requested. */
1446         if (options.compression) {
1447                 debug("Requesting compression at level %d.",
1448                     options.compression_level);
1449
1450                 if (options.compression_level < 1 ||
1451                     options.compression_level > 9)
1452                         fatal("Compression level must be from 1 (fast) to "
1453                             "9 (slow, best).");
1454
1455                 /* Send the request. */
1456                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
1457                 packet_put_int(options.compression_level);
1458                 packet_send();
1459                 packet_write_wait();
1460                 type = packet_read();
1461                 if (type == SSH_SMSG_SUCCESS)
1462                         packet_start_compression(options.compression_level);
1463                 else if (type == SSH_SMSG_FAILURE)
1464                         logit("Warning: Remote host refused compression.");
1465                 else
1466                         packet_disconnect("Protocol error waiting for "
1467                             "compression response.");
1468         }
1469         /* Allocate a pseudo tty if appropriate. */
1470         if (tty_flag) {
1471                 debug("Requesting pty.");
1472
1473                 /* Start the packet. */
1474                 packet_start(SSH_CMSG_REQUEST_PTY);
1475
1476                 /* Store TERM in the packet.  There is no limit on the
1477                    length of the string. */
1478                 cp = getenv("TERM");
1479                 if (!cp)
1480                         cp = "";
1481                 packet_put_cstring(cp);
1482
1483                 /* Store window size in the packet. */
1484                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
1485                         memset(&ws, 0, sizeof(ws));
1486                 packet_put_int((u_int)ws.ws_row);
1487                 packet_put_int((u_int)ws.ws_col);
1488                 packet_put_int((u_int)ws.ws_xpixel);
1489                 packet_put_int((u_int)ws.ws_ypixel);
1490
1491                 /* Store tty modes in the packet. */
1492                 tty_make_modes(fileno(stdin), NULL);
1493
1494                 /* Send the packet, and wait for it to leave. */
1495                 packet_send();
1496                 packet_write_wait();
1497
1498                 /* Read response from the server. */
1499                 type = packet_read();
1500                 if (type == SSH_SMSG_SUCCESS) {
1501                         interactive = 1;
1502                         have_tty = 1;
1503                 } else if (type == SSH_SMSG_FAILURE)
1504                         logit("Warning: Remote host failed or refused to "
1505                             "allocate a pseudo tty.");
1506                 else
1507                         packet_disconnect("Protocol error waiting for pty "
1508                             "request response.");
1509         }
1510         /* Request X11 forwarding if enabled and DISPLAY is set. */
1511         display = getenv("DISPLAY");
1512         if (options.forward_x11 && display != NULL) {
1513                 char *proto, *data;
1514                 /* Get reasonable local authentication information. */
1515                 client_x11_get_proto(display, options.xauth_location,
1516                     options.forward_x11_trusted,
1517                     options.forward_x11_timeout,
1518                     &proto, &data);
1519                 /* Request forwarding with authentication spoofing. */
1520                 debug("Requesting X11 forwarding with authentication "
1521                     "spoofing.");
1522                 x11_request_forwarding_with_spoofing(0, display, proto,
1523                     data, 0);
1524                 /* Read response from the server. */
1525                 type = packet_read();
1526                 if (type == SSH_SMSG_SUCCESS) {
1527                         interactive = 1;
1528                 } else if (type == SSH_SMSG_FAILURE) {
1529                         logit("Warning: Remote host denied X11 forwarding.");
1530                 } else {
1531                         packet_disconnect("Protocol error waiting for X11 "
1532                             "forwarding");
1533                 }
1534         }
1535         /* Tell the packet module whether this is an interactive session. */
1536         packet_set_interactive(interactive,
1537             options.ip_qos_interactive, options.ip_qos_bulk);
1538
1539         /* Request authentication agent forwarding if appropriate. */
1540         check_agent_present();
1541
1542         if (options.forward_agent) {
1543                 debug("Requesting authentication agent forwarding.");
1544                 auth_request_forwarding();
1545
1546                 /* Read response from the server. */
1547                 type = packet_read();
1548                 packet_check_eom();
1549                 if (type != SSH_SMSG_SUCCESS)
1550                         logit("Warning: Remote host denied authentication agent forwarding.");
1551         }
1552
1553         /* Initiate port forwardings. */
1554         ssh_init_stdio_forwarding();
1555         ssh_init_forwarding();
1556
1557         /* Execute a local command */
1558         if (options.local_command != NULL &&
1559             options.permit_local_command)
1560                 ssh_local_cmd(options.local_command);
1561
1562         /*
1563          * If requested and we are not interested in replies to remote
1564          * forwarding requests, then let ssh continue in the background.
1565          */
1566         if (fork_after_authentication_flag) {
1567                 if (options.exit_on_forward_failure &&
1568                     options.num_remote_forwards > 0) {
1569                         debug("deferring postauth fork until remote forward "
1570                             "confirmation received");
1571                 } else
1572                         fork_postauth();
1573         }
1574
1575         /*
1576          * If a command was specified on the command line, execute the
1577          * command now. Otherwise request the server to start a shell.
1578          */
1579         if (buffer_len(&command) > 0) {
1580                 int len = buffer_len(&command);
1581                 if (len > 900)
1582                         len = 900;
1583                 debug("Sending command: %.*s", len,
1584                     (u_char *)buffer_ptr(&command));
1585                 packet_start(SSH_CMSG_EXEC_CMD);
1586                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1587                 packet_send();
1588                 packet_write_wait();
1589         } else {
1590                 debug("Requesting shell.");
1591                 packet_start(SSH_CMSG_EXEC_SHELL);
1592                 packet_send();
1593                 packet_write_wait();
1594         }
1595
1596         /* Enter the interactive session. */
1597         return client_loop(have_tty, tty_flag ?
1598             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1599 }
1600
1601 /* request pty/x11/agent/tcpfwd/shell for channel */
1602 static void
1603 ssh_session2_setup(int id, int success, void *arg)
1604 {
1605         extern char **environ;
1606         const char *display;
1607         int interactive = tty_flag;
1608
1609         if (!success)
1610                 return; /* No need for error message, channels code sens one */
1611
1612         display = getenv("DISPLAY");
1613         if (options.forward_x11 && display != NULL) {
1614                 char *proto, *data;
1615                 /* Get reasonable local authentication information. */
1616                 client_x11_get_proto(display, options.xauth_location,
1617                     options.forward_x11_trusted,
1618                     options.forward_x11_timeout, &proto, &data);
1619                 /* Request forwarding with authentication spoofing. */
1620                 debug("Requesting X11 forwarding with authentication "
1621                     "spoofing.");
1622                 x11_request_forwarding_with_spoofing(id, display, proto,
1623                     data, 1);
1624                 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN);
1625                 /* XXX exit_on_forward_failure */
1626                 interactive = 1;
1627         }
1628
1629         check_agent_present();
1630         if (options.forward_agent) {
1631                 debug("Requesting authentication agent forwarding.");
1632                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1633                 packet_send();
1634         }
1635
1636         /* Tell the packet module whether this is an interactive session. */
1637         packet_set_interactive(interactive,
1638             options.ip_qos_interactive, options.ip_qos_bulk);
1639
1640         client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1641             NULL, fileno(stdin), &command, environ);
1642 }
1643
1644 /* open new channel for a session */
1645 static int
1646 ssh_session2_open(void)
1647 {
1648         Channel *c;
1649         int window, packetmax, in, out, err;
1650
1651         if (stdin_null_flag) {
1652                 in = open(_PATH_DEVNULL, O_RDONLY);
1653         } else {
1654                 in = dup(STDIN_FILENO);
1655         }
1656         out = dup(STDOUT_FILENO);
1657         err = dup(STDERR_FILENO);
1658
1659         if (in < 0 || out < 0 || err < 0)
1660                 fatal("dup() in/out/err failed");
1661
1662         /* enable nonblocking unless tty */
1663         if (!isatty(in))
1664                 set_nonblock(in);
1665         if (!isatty(out))
1666                 set_nonblock(out);
1667         if (!isatty(err))
1668                 set_nonblock(err);
1669
1670         /*
1671          * We need to check to see what to do about buffer sizes here.
1672          * - In an HPN to non-HPN connection we want to limit the window size to
1673          *   something reasonable in case the far side has the large window bug.
1674          * - In an HPN to HPN connection we want to use the max window size but
1675          *   allow the user to override it.
1676          * - Lastly if HPN is disabled then use the ssh standard window size.
1677          *
1678          * We cannot just do a getsockopt() here and set the ssh window to that
1679          * as in case of autotuning of socket buffers the window would get stuck
1680          * at the initial buffer size, generally less than 96k.  Therefore we
1681          * need to set the maximum ssh window size to the maximum HPN buffer
1682          * size unless the user has set TcpRcvBufPoll to no.  In that case we
1683          * can just set the window to the minimum of HPN buffer size and TCP
1684          * receive buffer size.
1685          */
1686         if (tty_flag)
1687                 options.hpn_buffer_size = CHAN_SES_WINDOW_DEFAULT;
1688         else
1689                 options.hpn_buffer_size = CHAN_HPN_MIN_WINDOW_DEFAULT;
1690
1691         if (datafellows & SSH_BUG_LARGEWINDOW) {
1692                 debug("HPN to Non-HPN Connection");
1693         } else if (options.tcp_rcv_buf_poll <= 0) {
1694                 sock_get_rcvbuf(&options.hpn_buffer_size, 0);
1695                 debug("HPNBufferSize set to TCP RWIN: %d",
1696                     options.hpn_buffer_size);
1697         } else if (options.tcp_rcv_buf > 0) {
1698                 sock_get_rcvbuf(&options.hpn_buffer_size,
1699                     options.tcp_rcv_buf);
1700                 debug("HPNBufferSize set to user TCPRcvBuf: %d",
1701                     options.hpn_buffer_size);
1702         }
1703         debug("Final hpn_buffer_size = %d", options.hpn_buffer_size);
1704         channel_set_hpn(options.hpn_disabled, options.hpn_buffer_size);
1705         window = options.hpn_buffer_size;
1706
1707         packetmax = CHAN_SES_PACKET_DEFAULT;
1708         if (tty_flag) {
1709                 window = CHAN_SES_WINDOW_DEFAULT;
1710                 window >>= 1;
1711                 packetmax >>= 1;
1712         }
1713         c = channel_new(
1714             "session", SSH_CHANNEL_OPENING, in, out, err,
1715             window, packetmax, CHAN_EXTENDED_WRITE,
1716             "client-session", /*nonblock*/0);
1717         if (!options.hpn_disabled && options.tcp_rcv_buf_poll > 0) {
1718                 c->dynamic_window = 1;
1719                 debug("Enabled Dynamic Window Scaling\n");
1720         }
1721
1722         debug3("ssh_session2_open: channel_new: %d", c->self);
1723
1724         channel_send_open(c->self);
1725         if (!no_shell_flag)
1726                 channel_register_open_confirm(c->self,
1727                     ssh_session2_setup, NULL);
1728
1729         return c->self;
1730 }
1731
1732 static int
1733 ssh_session2(void)
1734 {
1735         int id = -1;
1736
1737         /* XXX should be pre-session */
1738         if (!options.control_persist)
1739                 ssh_init_stdio_forwarding();
1740         ssh_init_forwarding();
1741
1742         /* Start listening for multiplex clients */
1743         muxserver_listen();
1744
1745         /*
1746          * If we are in control persist mode and have a working mux listen
1747          * socket, then prepare to background ourselves and have a foreground
1748          * client attach as a control slave.
1749          * NB. we must save copies of the flags that we override for
1750          * the backgrounding, since we defer attachment of the slave until
1751          * after the connection is fully established (in particular,
1752          * async rfwd replies have been received for ExitOnForwardFailure).
1753          */
1754         if (options.control_persist && muxserver_sock != -1) {
1755                 ostdin_null_flag = stdin_null_flag;
1756                 ono_shell_flag = no_shell_flag;
1757                 orequest_tty = options.request_tty;
1758                 otty_flag = tty_flag;
1759                 stdin_null_flag = 1;
1760                 no_shell_flag = 1;
1761                 tty_flag = 0;
1762                 if (!fork_after_authentication_flag)
1763                         need_controlpersist_detach = 1;
1764                 fork_after_authentication_flag = 1;
1765         }
1766         /*
1767          * ControlPersist mux listen socket setup failed, attempt the
1768          * stdio forward setup that we skipped earlier.
1769          */
1770         if (options.control_persist && muxserver_sock == -1)
1771                 ssh_init_stdio_forwarding();
1772
1773         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1774                 id = ssh_session2_open();
1775         else {
1776                 packet_set_interactive(
1777                     options.control_master == SSHCTL_MASTER_NO,
1778                     options.ip_qos_interactive, options.ip_qos_bulk);
1779         }
1780
1781         /* If we don't expect to open a new session, then disallow it */
1782         if (options.control_master == SSHCTL_MASTER_NO &&
1783             (datafellows & SSH_NEW_OPENSSH)) {
1784                 debug("Requesting no-more-sessions@openssh.com");
1785                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1786                 packet_put_cstring("no-more-sessions@openssh.com");
1787                 packet_put_char(0);
1788                 packet_send();
1789         }
1790
1791         /* Execute a local command */
1792         if (options.local_command != NULL &&
1793             options.permit_local_command)
1794                 ssh_local_cmd(options.local_command);
1795
1796         /*
1797          * If requested and we are not interested in replies to remote
1798          * forwarding requests, then let ssh continue in the background.
1799          */
1800         if (fork_after_authentication_flag) {
1801                 if (options.exit_on_forward_failure &&
1802                     options.num_remote_forwards > 0) {
1803                         debug("deferring postauth fork until remote forward "
1804                             "confirmation received");
1805                 } else
1806                         fork_postauth();
1807         }
1808
1809         if (options.use_roaming)
1810                 request_roaming();
1811
1812         return client_loop(tty_flag, tty_flag ?
1813             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1814 }
1815
1816 static void
1817 load_public_identity_files(void)
1818 {
1819         char *filename, *cp, thishost[NI_MAXHOST];
1820         char *pwdir = NULL, *pwname = NULL;
1821         int i = 0;
1822         Key *public;
1823         struct passwd *pw;
1824         u_int n_ids;
1825         char *identity_files[SSH_MAX_IDENTITY_FILES];
1826         Key *identity_keys[SSH_MAX_IDENTITY_FILES];
1827 #ifdef ENABLE_PKCS11
1828         Key **keys;
1829         int nkeys;
1830 #endif /* PKCS11 */
1831
1832         n_ids = 0;
1833         memset(identity_files, 0, sizeof(identity_files));
1834         memset(identity_keys, 0, sizeof(identity_keys));
1835
1836 #ifdef ENABLE_PKCS11
1837         if (options.pkcs11_provider != NULL &&
1838             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1839             (pkcs11_init(!options.batch_mode) == 0) &&
1840             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
1841             &keys)) > 0) {
1842                 for (i = 0; i < nkeys; i++) {
1843                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
1844                                 key_free(keys[i]);
1845                                 continue;
1846                         }
1847                         identity_keys[n_ids] = keys[i];
1848                         identity_files[n_ids] =
1849                             xstrdup(options.pkcs11_provider); /* XXX */
1850                         n_ids++;
1851                 }
1852                 free(keys);
1853         }
1854 #endif /* ENABLE_PKCS11 */
1855         if ((pw = getpwuid(original_real_uid)) == NULL)
1856                 fatal("load_public_identity_files: getpwuid failed");
1857         pwname = xstrdup(pw->pw_name);
1858         pwdir = xstrdup(pw->pw_dir);
1859         if (gethostname(thishost, sizeof(thishost)) == -1)
1860                 fatal("load_public_identity_files: gethostname: %s",
1861                     strerror(errno));
1862         for (i = 0; i < options.num_identity_files; i++) {
1863                 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
1864                     strcasecmp(options.identity_files[i], "none") == 0) {
1865                         free(options.identity_files[i]);
1866                         continue;
1867                 }
1868                 cp = tilde_expand_filename(options.identity_files[i],
1869                     original_real_uid);
1870                 filename = percent_expand(cp, "d", pwdir,
1871                     "u", pwname, "l", thishost, "h", host,
1872                     "r", options.user, (char *)NULL);
1873                 free(cp);
1874                 public = key_load_public(filename, NULL);
1875                 debug("identity file %s type %d", filename,
1876                     public ? public->type : -1);
1877                 free(options.identity_files[i]);
1878                 identity_files[n_ids] = filename;
1879                 identity_keys[n_ids] = public;
1880
1881                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
1882                         continue;
1883
1884                 /* Try to add the certificate variant too */
1885                 xasprintf(&cp, "%s-cert", filename);
1886                 public = key_load_public(cp, NULL);
1887                 debug("identity file %s type %d", cp,
1888                     public ? public->type : -1);
1889                 if (public == NULL) {
1890                         free(cp);
1891                         continue;
1892                 }
1893                 if (!key_is_cert(public)) {
1894                         debug("%s: key %s type %s is not a certificate",
1895                             __func__, cp, key_type(public));
1896                         key_free(public);
1897                         free(cp);
1898                         continue;
1899                 }
1900                 identity_keys[n_ids] = public;
1901                 /* point to the original path, most likely the private key */
1902                 identity_files[n_ids] = xstrdup(filename);
1903                 n_ids++;
1904         }
1905         options.num_identity_files = n_ids;
1906         memcpy(options.identity_files, identity_files, sizeof(identity_files));
1907         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
1908
1909         explicit_bzero(pwname, strlen(pwname));
1910         free(pwname);
1911         explicit_bzero(pwdir, strlen(pwdir));
1912         free(pwdir);
1913 }
1914
1915 static void
1916 main_sigchld_handler(int sig)
1917 {
1918         int save_errno = errno;
1919         pid_t pid;
1920         int status;
1921
1922         while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
1923             (pid < 0 && errno == EINTR))
1924                 ;
1925
1926         signal(sig, main_sigchld_handler);
1927         errno = save_errno;
1928 }