crypto/openssh-4/readconf.c

   1 /*
   2  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   3  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   4  *                    All rights reserved
   5  * Functions for reading the configuration files.
   6  *
   7  * As far as I am concerned, the code I have written for this software
   8  * can be used freely for any purpose.  Any derived versions of this
   9  * software must be clearly marked as such, and if the derived work is
  10  * incompatible with the protocol description in the RFC file, it must be
  11  * called by a name other than "ssh" or "Secure Shell".
  12  */
  13
  14 #include "includes.h"
  15 RCSID("$OpenBSD: readconf.c,v 1.139 2005/03/10 22:01:05 deraadt Exp $");
  16
  17 #include "ssh.h"
  18 #include "xmalloc.h"
  19 #include "compat.h"
  20 #include "cipher.h"
  21 #include "pathnames.h"
  22 #include "log.h"
  23 #include "readconf.h"
  24 #include "match.h"
  25 #include "misc.h"
  26 #include "kex.h"
  27 #include "mac.h"
  28
  29 /* Format of the configuration file:
  30
  31    # Configuration data is parsed as follows:
  32    #  1. command line options
  33    #  2. user-specific file
  34    #  3. system-wide file
  35    # Any configuration value is only changed the first time it is set.
  36    # Thus, host-specific definitions should be at the beginning of the
  37    # configuration file, and defaults at the end.
  38
  39    # Host-specific declarations.  These may override anything above.  A single
  40    # host may match multiple declarations; these are processed in the order
  41    # that they are given in.
  42
  43    Host *.ngs.fi ngs.fi
  44      User foo
  45
  46    Host fake.com
  47      HostName another.host.name.real.org
  48      User blaah
  49      Port 34289
  50      ForwardX11 no
  51      ForwardAgent no
  52
  53    Host books.com
  54      RemoteForward 9999 shadows.cs.hut.fi:9999
  55      Cipher 3des
  56
  57    Host fascist.blob.com
  58      Port 23123
  59      User tylonen
  60      PasswordAuthentication no
  61
  62    Host puukko.hut.fi
  63      User t35124p
  64      ProxyCommand ssh-proxy %h %p
  65
  66    Host *.fr
  67      PublicKeyAuthentication no
  68
  69    Host *.su
  70      Cipher none
  71      PasswordAuthentication no
  72
  73    # Defaults for various options
  74    Host *
  75      ForwardAgent no
  76      ForwardX11 no
  77      PasswordAuthentication yes
  78      RSAAuthentication yes
  79      RhostsRSAAuthentication yes
  80      StrictHostKeyChecking yes
  81      TcpKeepAlive no
  82      IdentityFile ~/.ssh/identity
  83      Port 22
  84      EscapeChar ~
  85
  86 */
  87
  88 /* Keyword tokens. */
  89
  90 typedef enum {
  91         oBadOption,
  92         oForwardAgent, oForwardX11, oForwardX11Trusted, oGatewayPorts,
  93         oPasswordAuthentication, oRSAAuthentication,
  94         oChallengeResponseAuthentication, oXAuthLocation,
  95         oIdentityFile, oHostName, oPort, oCipher, oRemoteForward, oLocalForward,
  96         oUser, oHost, oEscapeChar, oRhostsRSAAuthentication, oProxyCommand,
  97         oGlobalKnownHostsFile, oUserKnownHostsFile, oConnectionAttempts,
  98         oBatchMode, oCheckHostIP, oStrictHostKeyChecking, oCompression,
  99         oCompressionLevel, oTCPKeepAlive, oNumberOfPasswordPrompts,
 100         oUsePrivilegedPort, oLogLevel, oCiphers, oProtocol, oMacs,
 101         oGlobalKnownHostsFile2, oUserKnownHostsFile2, oPubkeyAuthentication,
 102         oKbdInteractiveAuthentication, oKbdInteractiveDevices, oHostKeyAlias,
 103         oDynamicForward, oPreferredAuthentications, oHostbasedAuthentication,
 104         oHostKeyAlgorithms, oBindAddress, oSmartcardDevice,
 105         oClearAllForwardings, oNoHostAuthenticationForLocalhost,
 106         oEnableSSHKeysign, oRekeyLimit, oVerifyHostKeyDNS, oConnectTimeout,
 107         oAddressFamily, oGssAuthentication, oGssDelegateCreds,
 108         oServerAliveInterval, oServerAliveCountMax, oIdentitiesOnly,
 109         oSendEnv, oControlPath, oControlMaster, oHashKnownHosts,
 110         oDeprecated, oUnsupported
 111 } OpCodes;
 112
 113 /* Textual representations of the tokens. */
 114
 115 static struct {
 116         const char *name;
 117         OpCodes opcode;
 118 } keywords[] = {
 119         { "forwardagent", oForwardAgent },
 120         { "forwardx11", oForwardX11 },
 121         { "forwardx11trusted", oForwardX11Trusted },
 122         { "xauthlocation", oXAuthLocation },
 123         { "gatewayports", oGatewayPorts },
 124         { "useprivilegedport", oUsePrivilegedPort },
 125         { "rhostsauthentication", oDeprecated },
 126         { "passwordauthentication", oPasswordAuthentication },
 127         { "kbdinteractiveauthentication", oKbdInteractiveAuthentication },
 128         { "kbdinteractivedevices", oKbdInteractiveDevices },
 129         { "rsaauthentication", oRSAAuthentication },
 130         { "pubkeyauthentication", oPubkeyAuthentication },
 131         { "dsaauthentication", oPubkeyAuthentication },             /* alias */
 132         { "rhostsrsaauthentication", oRhostsRSAAuthentication },
 133         { "hostbasedauthentication", oHostbasedAuthentication },
 134         { "challengeresponseauthentication", oChallengeResponseAuthentication },
 135         { "skeyauthentication", oChallengeResponseAuthentication }, /* alias */
 136         { "tisauthentication", oChallengeResponseAuthentication },  /* alias */
 137         { "kerberosauthentication", oUnsupported },
 138         { "kerberostgtpassing", oUnsupported },
 139         { "afstokenpassing", oUnsupported },
 140 #if defined(GSSAPI)
 141         { "gssapiauthentication", oGssAuthentication },
 142         { "gssapidelegatecredentials", oGssDelegateCreds },
 143 #else
 144         { "gssapiauthentication", oUnsupported },
 145         { "gssapidelegatecredentials", oUnsupported },
 146 #endif
 147         { "fallbacktorsh", oDeprecated },
 148         { "usersh", oDeprecated },
 149         { "identityfile", oIdentityFile },
 150         { "identityfile2", oIdentityFile },                     /* alias */
 151         { "identitiesonly", oIdentitiesOnly },
 152         { "hostname", oHostName },
 153         { "hostkeyalias", oHostKeyAlias },
 154         { "proxycommand", oProxyCommand },
 155         { "port", oPort },
 156         { "cipher", oCipher },
 157         { "ciphers", oCiphers },
 158         { "macs", oMacs },
 159         { "protocol", oProtocol },
 160         { "remoteforward", oRemoteForward },
 161         { "localforward", oLocalForward },
 162         { "user", oUser },
 163         { "host", oHost },
 164         { "escapechar", oEscapeChar },
 165         { "globalknownhostsfile", oGlobalKnownHostsFile },
 166         { "userknownhostsfile", oUserKnownHostsFile },          /* obsolete */
 167         { "globalknownhostsfile2", oGlobalKnownHostsFile2 },
 168         { "userknownhostsfile2", oUserKnownHostsFile2 },        /* obsolete */
 169         { "connectionattempts", oConnectionAttempts },
 170         { "batchmode", oBatchMode },
 171         { "checkhostip", oCheckHostIP },
 172         { "stricthostkeychecking", oStrictHostKeyChecking },
 173         { "compression", oCompression },
 174         { "compressionlevel", oCompressionLevel },
 175         { "tcpkeepalive", oTCPKeepAlive },
 176         { "keepalive", oTCPKeepAlive },                         /* obsolete */
 177         { "numberofpasswordprompts", oNumberOfPasswordPrompts },
 178         { "loglevel", oLogLevel },
 179         { "dynamicforward", oDynamicForward },
 180         { "preferredauthentications", oPreferredAuthentications },
 181         { "hostkeyalgorithms", oHostKeyAlgorithms },
 182         { "bindaddress", oBindAddress },
 183 #ifdef SMARTCARD
 184         { "smartcarddevice", oSmartcardDevice },
 185 #else
 186         { "smartcarddevice", oUnsupported },
 187 #endif
 188         { "clearallforwardings", oClearAllForwardings },
 189         { "enablesshkeysign", oEnableSSHKeysign },
 190         { "verifyhostkeydns", oVerifyHostKeyDNS },
 191         { "nohostauthenticationforlocalhost", oNoHostAuthenticationForLocalhost },
 192         { "rekeylimit", oRekeyLimit },
 193         { "connecttimeout", oConnectTimeout },
 194         { "addressfamily", oAddressFamily },
 195         { "serveraliveinterval", oServerAliveInterval },
 196         { "serveralivecountmax", oServerAliveCountMax },
 197         { "sendenv", oSendEnv },
 198         { "controlpath", oControlPath },
 199         { "controlmaster", oControlMaster },
 200         { "hashknownhosts", oHashKnownHosts },
 201         { NULL, oBadOption }
 202 };
 203
 204 /*
 205  * Adds a local TCP/IP port forward to options.  Never returns if there is an
 206  * error.
 207  */
 208
 209 void
 210 add_local_forward(Options *options, const Forward *newfwd)
 211 {
 212         Forward *fwd;
 213 #ifndef NO_IPPORT_RESERVED_CONCEPT
 214         extern uid_t original_real_uid;
 215         if (newfwd->listen_port < IPPORT_RESERVED && original_real_uid != 0)
 216                 fatal("Privileged ports can only be forwarded by root.");
 217 #endif
 218         if (options->num_local_forwards >= SSH_MAX_FORWARDS_PER_DIRECTION)
 219                 fatal("Too many local forwards (max %d).", SSH_MAX_FORWARDS_PER_DIRECTION);
 220         fwd = &options->local_forwards[options->num_local_forwards++];
 221
 222         fwd->listen_host = (newfwd->listen_host == NULL) ?
 223             NULL : xstrdup(newfwd->listen_host);
 224         fwd->listen_port = newfwd->listen_port;
 225         fwd->connect_host = xstrdup(newfwd->connect_host);
 226         fwd->connect_port = newfwd->connect_port;
 227 }
 228
 229 /*
 230  * Adds a remote TCP/IP port forward to options.  Never returns if there is
 231  * an error.
 232  */
 233
 234 void
 235 add_remote_forward(Options *options, const Forward *newfwd)
 236 {
 237         Forward *fwd;
 238         if (options->num_remote_forwards >= SSH_MAX_FORWARDS_PER_DIRECTION)
 239                 fatal("Too many remote forwards (max %d).",
 240                     SSH_MAX_FORWARDS_PER_DIRECTION);
 241         fwd = &options->remote_forwards[options->num_remote_forwards++];
 242
 243         fwd->listen_host = (newfwd->listen_host == NULL) ?
 244             NULL : xstrdup(newfwd->listen_host);
 245         fwd->listen_port = newfwd->listen_port;
 246         fwd->connect_host = xstrdup(newfwd->connect_host);
 247         fwd->connect_port = newfwd->connect_port;
 248 }
 249
 250 static void
 251 clear_forwardings(Options *options)
 252 {
 253         int i;
 254
 255         for (i = 0; i < options->num_local_forwards; i++) {
 256                 if (options->local_forwards[i].listen_host != NULL)
 257                         xfree(options->local_forwards[i].listen_host);
 258                 xfree(options->local_forwards[i].connect_host);
 259         }
 260         options->num_local_forwards = 0;
 261         for (i = 0; i < options->num_remote_forwards; i++) {
 262                 if (options->remote_forwards[i].listen_host != NULL)
 263                         xfree(options->remote_forwards[i].listen_host);
 264                 xfree(options->remote_forwards[i].connect_host);
 265         }
 266         options->num_remote_forwards = 0;
 267 }
 268
 269 /*
 270  * Returns the number of the token pointed to by cp or oBadOption.
 271  */
 272
 273 static OpCodes
 274 parse_token(const char *cp, const char *filename, int linenum)
 275 {
 276         u_int i;
 277
 278         for (i = 0; keywords[i].name; i++)
 279                 if (strcasecmp(cp, keywords[i].name) == 0)
 280                         return keywords[i].opcode;
 281
 282         error("%s: line %d: Bad configuration option: %s",
 283             filename, linenum, cp);
 284         return oBadOption;
 285 }
 286
 287 /*
 288  * Processes a single option line as used in the configuration files. This
 289  * only sets those values that have not already been set.
 290  */
 291 #define WHITESPACE " \t\r\n"
 292
 293 int
 294 process_config_line(Options *options, const char *host,
 295                     char *line, const char *filename, int linenum,
 296                     int *activep)
 297 {
 298         char *s, **charptr, *endofnumber, *keyword, *arg, *arg2, fwdarg[256];
 299         int opcode, *intptr, value;
 300         size_t len;
 301         Forward fwd;
 302
 303         /* Strip trailing whitespace */
 304         for (len = strlen(line) - 1; len > 0; len--) {
 305                 if (strchr(WHITESPACE, line[len]) == NULL)
 306                         break;
 307                 line[len] = '\0';
 308         }
 309
 310         s = line;
 311         /* Get the keyword. (Each line is supposed to begin with a keyword). */
 312         keyword = strdelim(&s);
 313         /* Ignore leading whitespace. */
 314         if (*keyword == '\0')
 315                 keyword = strdelim(&s);
 316         if (keyword == NULL || !*keyword || *keyword == '\n' || *keyword == '#')
 317                 return 0;
 318
 319         opcode = parse_token(keyword, filename, linenum);
 320
 321         switch (opcode) {
 322         case oBadOption:
 323                 /* don't panic, but count bad options */
 324                 return -1;
 325                 /* NOTREACHED */
 326         case oConnectTimeout:
 327                 intptr = &options->connection_timeout;
 328 parse_time:
 329                 arg = strdelim(&s);
 330                 if (!arg || *arg == '\0')
 331                         fatal("%s line %d: missing time value.",
 332                             filename, linenum);
 333                 if ((value = convtime(arg)) == -1)
 334                         fatal("%s line %d: invalid time value.",
 335                             filename, linenum);
 336                 if (*intptr == -1)
 337                         *intptr = value;
 338                 break;
 339
 340         case oForwardAgent:
 341                 intptr = &options->forward_agent;
 342 parse_flag:
 343                 arg = strdelim(&s);
 344                 if (!arg || *arg == '\0')
 345                         fatal("%.200s line %d: Missing yes/no argument.", filename, linenum);
 346                 value = 0;      /* To avoid compiler warning... */
 347                 if (strcmp(arg, "yes") == 0 || strcmp(arg, "true") == 0)
 348                         value = 1;
 349                 else if (strcmp(arg, "no") == 0 || strcmp(arg, "false") == 0)
 350                         value = 0;
 351                 else
 352                         fatal("%.200s line %d: Bad yes/no argument.", filename, linenum);
 353                 if (*activep && *intptr == -1)
 354                         *intptr = value;
 355                 break;
 356
 357         case oForwardX11:
 358                 intptr = &options->forward_x11;
 359                 goto parse_flag;
 360
 361         case oForwardX11Trusted:
 362                 intptr = &options->forward_x11_trusted;
 363                 goto parse_flag;
 364
 365         case oGatewayPorts:
 366                 intptr = &options->gateway_ports;
 367                 goto parse_flag;
 368
 369         case oUsePrivilegedPort:
 370                 intptr = &options->use_privileged_port;
 371                 goto parse_flag;
 372
 373         case oPasswordAuthentication:
 374                 intptr = &options->password_authentication;
 375                 goto parse_flag;
 376
 377         case oKbdInteractiveAuthentication:
 378                 intptr = &options->kbd_interactive_authentication;
 379                 goto parse_flag;
 380
 381         case oKbdInteractiveDevices:
 382                 charptr = &options->kbd_interactive_devices;
 383                 goto parse_string;
 384
 385         case oPubkeyAuthentication:
 386                 intptr = &options->pubkey_authentication;
 387                 goto parse_flag;
 388
 389         case oRSAAuthentication:
 390                 intptr = &options->rsa_authentication;
 391                 goto parse_flag;
 392
 393         case oRhostsRSAAuthentication:
 394                 intptr = &options->rhosts_rsa_authentication;
 395                 goto parse_flag;
 396
 397         case oHostbasedAuthentication:
 398                 intptr = &options->hostbased_authentication;
 399                 goto parse_flag;
 400
 401         case oChallengeResponseAuthentication:
 402                 intptr = &options->challenge_response_authentication;
 403                 goto parse_flag;
 404
 405         case oGssAuthentication:
 406                 intptr = &options->gss_authentication;
 407                 goto parse_flag;
 408
 409         case oGssDelegateCreds:
 410                 intptr = &options->gss_deleg_creds;
 411                 goto parse_flag;
 412
 413         case oBatchMode:
 414                 intptr = &options->batch_mode;
 415                 goto parse_flag;
 416
 417         case oCheckHostIP:
 418                 intptr = &options->check_host_ip;
 419                 goto parse_flag;
 420
 421         case oVerifyHostKeyDNS:
 422                 intptr = &options->verify_host_key_dns;
 423                 goto parse_yesnoask;
 424
 425         case oStrictHostKeyChecking:
 426                 intptr = &options->strict_host_key_checking;
 427 parse_yesnoask:
 428                 arg = strdelim(&s);
 429                 if (!arg || *arg == '\0')
 430                         fatal("%.200s line %d: Missing yes/no/ask argument.",
 431                             filename, linenum);
 432                 value = 0;      /* To avoid compiler warning... */
 433                 if (strcmp(arg, "yes") == 0 || strcmp(arg, "true") == 0)
 434                         value = 1;
 435                 else if (strcmp(arg, "no") == 0 || strcmp(arg, "false") == 0)
 436                         value = 0;
 437                 else if (strcmp(arg, "ask") == 0)
 438                         value = 2;
 439                 else
 440                         fatal("%.200s line %d: Bad yes/no/ask argument.", filename, linenum);
 441                 if (*activep && *intptr == -1)
 442                         *intptr = value;
 443                 break;
 444
 445         case oCompression:
 446                 intptr = &options->compression;
 447                 goto parse_flag;
 448
 449         case oTCPKeepAlive:
 450                 intptr = &options->tcp_keep_alive;
 451                 goto parse_flag;
 452
 453         case oNoHostAuthenticationForLocalhost:
 454                 intptr = &options->no_host_authentication_for_localhost;
 455                 goto parse_flag;
 456
 457         case oNumberOfPasswordPrompts:
 458                 intptr = &options->number_of_password_prompts;
 459                 goto parse_int;
 460
 461         case oCompressionLevel:
 462                 intptr = &options->compression_level;
 463                 goto parse_int;
 464
 465         case oRekeyLimit:
 466                 intptr = &options->rekey_limit;
 467                 arg = strdelim(&s);
 468                 if (!arg || *arg == '\0')
 469                         fatal("%.200s line %d: Missing argument.", filename, linenum);
 470                 if (arg[0] < '0' || arg[0] > '9')
 471                         fatal("%.200s line %d: Bad number.", filename, linenum);
 472                 value = strtol(arg, &endofnumber, 10);
 473                 if (arg == endofnumber)
 474                         fatal("%.200s line %d: Bad number.", filename, linenum);
 475                 switch (toupper(*endofnumber)) {
 476                 case 'K':
 477                         value *= 1<<10;
 478                         break;
 479                 case 'M':
 480                         value *= 1<<20;
 481                         break;
 482                 case 'G':
 483                         value *= 1<<30;
 484                         break;
 485                 }
 486                 if (*activep && *intptr == -1)
 487                         *intptr = value;
 488                 break;
 489
 490         case oIdentityFile:
 491                 arg = strdelim(&s);
 492                 if (!arg || *arg == '\0')
 493                         fatal("%.200s line %d: Missing argument.", filename, linenum);
 494                 if (*activep) {
 495                         intptr = &options->num_identity_files;
 496                         if (*intptr >= SSH_MAX_IDENTITY_FILES)
 497                                 fatal("%.200s line %d: Too many identity files specified (max %d).",
 498                                     filename, linenum, SSH_MAX_IDENTITY_FILES);
 499                         charptr =  &options->identity_files[*intptr];
 500                         *charptr = xstrdup(arg);
 501                         *intptr = *intptr + 1;
 502                 }
 503                 break;
 504
 505         case oXAuthLocation:
 506                 charptr=&options->xauth_location;
 507                 goto parse_string;
 508
 509         case oUser:
 510                 charptr = &options->user;
 511 parse_string:
 512                 arg = strdelim(&s);
 513                 if (!arg || *arg == '\0')
 514                         fatal("%.200s line %d: Missing argument.", filename, linenum);
 515                 if (*activep && *charptr == NULL)
 516                         *charptr = xstrdup(arg);
 517                 break;
 518
 519         case oGlobalKnownHostsFile:
 520                 charptr = &options->system_hostfile;
 521                 goto parse_string;
 522
 523         case oUserKnownHostsFile:
 524                 charptr = &options->user_hostfile;
 525                 goto parse_string;
 526
 527         case oGlobalKnownHostsFile2:
 528                 charptr = &options->system_hostfile2;
 529                 goto parse_string;
 530
 531         case oUserKnownHostsFile2:
 532                 charptr = &options->user_hostfile2;
 533                 goto parse_string;
 534
 535         case oHostName:
 536                 charptr = &options->hostname;
 537                 goto parse_string;
 538
 539         case oHostKeyAlias:
 540                 charptr = &options->host_key_alias;
 541                 goto parse_string;
 542
 543         case oPreferredAuthentications:
 544                 charptr = &options->preferred_authentications;
 545                 goto parse_string;
 546
 547         case oBindAddress:
 548                 charptr = &options->bind_address;
 549                 goto parse_string;
 550
 551         case oSmartcardDevice:
 552                 charptr = &options->smartcard_device;
 553                 goto parse_string;
 554
 555         case oProxyCommand:
 556                 if (s == NULL)
 557                         fatal("%.200s line %d: Missing argument.", filename, linenum);
 558                 charptr = &options->proxy_command;
 559                 len = strspn(s, WHITESPACE "=");
 560                 if (*activep && *charptr == NULL)
 561                         *charptr = xstrdup(s + len);
 562                 return 0;
 563
 564         case oPort:
 565                 intptr = &options->port;
 566 parse_int:
 567                 arg = strdelim(&s);
 568                 if (!arg || *arg == '\0')
 569                         fatal("%.200s line %d: Missing argument.", filename, linenum);
 570                 if (arg[0] < '0' || arg[0] > '9')
 571                         fatal("%.200s line %d: Bad number.", filename, linenum);
 572
 573                 /* Octal, decimal, or hex format? */
 574                 value = strtol(arg, &endofnumber, 0);
 575                 if (arg == endofnumber)
 576                         fatal("%.200s line %d: Bad number.", filename, linenum);
 577                 if (*activep && *intptr == -1)
 578                         *intptr = value;
 579                 break;
 580
 581         case oConnectionAttempts:
 582                 intptr = &options->connection_attempts;
 583                 goto parse_int;
 584
 585         case oCipher:
 586                 intptr = &options->cipher;
 587                 arg = strdelim(&s);
 588                 if (!arg || *arg == '\0')
 589                         fatal("%.200s line %d: Missing argument.", filename, linenum);
 590                 value = cipher_number(arg);
 591                 if (value == -1)
 592                         fatal("%.200s line %d: Bad cipher '%s'.",
 593                             filename, linenum, arg ? arg : "<NONE>");
 594                 if (*activep && *intptr == -1)
 595                         *intptr = value;
 596                 break;
 597
 598         case oCiphers:
 599                 arg = strdelim(&s);
 600                 if (!arg || *arg == '\0')
 601                         fatal("%.200s line %d: Missing argument.", filename, linenum);
 602                 if (!ciphers_valid(arg))
 603                         fatal("%.200s line %d: Bad SSH2 cipher spec '%s'.",
 604                             filename, linenum, arg ? arg : "<NONE>");
 605                 if (*activep && options->ciphers == NULL)
 606                         options->ciphers = xstrdup(arg);
 607                 break;
 608
 609         case oMacs:
 610                 arg = strdelim(&s);
 611                 if (!arg || *arg == '\0')
 612                         fatal("%.200s line %d: Missing argument.", filename, linenum);
 613                 if (!mac_valid(arg))
 614                         fatal("%.200s line %d: Bad SSH2 Mac spec '%s'.",
 615                             filename, linenum, arg ? arg : "<NONE>");
 616                 if (*activep && options->macs == NULL)
 617                         options->macs = xstrdup(arg);
 618                 break;
 619
 620         case oHostKeyAlgorithms:
 621                 arg = strdelim(&s);
 622                 if (!arg || *arg == '\0')
 623                         fatal("%.200s line %d: Missing argument.", filename, linenum);
 624                 if (!key_names_valid2(arg))
 625                         fatal("%.200s line %d: Bad protocol 2 host key algorithms '%s'.",
 626                             filename, linenum, arg ? arg : "<NONE>");
 627                 if (*activep && options->hostkeyalgorithms == NULL)
 628                         options->hostkeyalgorithms = xstrdup(arg);
 629                 break;
 630
 631         case oProtocol:
 632                 intptr = &options->protocol;
 633                 arg = strdelim(&s);
 634                 if (!arg || *arg == '\0')
 635                         fatal("%.200s line %d: Missing argument.", filename, linenum);
 636                 value = proto_spec(arg);
 637                 if (value == SSH_PROTO_UNKNOWN)
 638                         fatal("%.200s line %d: Bad protocol spec '%s'.",
 639                             filename, linenum, arg ? arg : "<NONE>");
 640                 if (*activep && *intptr == SSH_PROTO_UNKNOWN)
 641                         *intptr = value;
 642                 break;
 643
 644         case oLogLevel:
 645                 intptr = (int *) &options->log_level;
 646                 arg = strdelim(&s);
 647                 value = log_level_number(arg);
 648                 if (value == SYSLOG_LEVEL_NOT_SET)
 649                         fatal("%.200s line %d: unsupported log level '%s'",
 650                             filename, linenum, arg ? arg : "<NONE>");
 651                 if (*activep && (LogLevel) *intptr == SYSLOG_LEVEL_NOT_SET)
 652                         *intptr = (LogLevel) value;
 653                 break;
 654
 655         case oLocalForward:
 656         case oRemoteForward:
 657                 arg = strdelim(&s);
 658                 if (arg == NULL || *arg == '\0')
 659                         fatal("%.200s line %d: Missing port argument.",
 660                             filename, linenum);
 661                 arg2 = strdelim(&s);
 662                 if (arg2 == NULL || *arg2 == '\0')
 663                         fatal("%.200s line %d: Missing target argument.",
 664                             filename, linenum);
 665
 666                 /* construct a string for parse_forward */
 667                 snprintf(fwdarg, sizeof(fwdarg), "%s:%s", arg, arg2);
 668
 669                 if (parse_forward(&fwd, fwdarg) == 0)
 670                         fatal("%.200s line %d: Bad forwarding specification.",
 671                             filename, linenum);
 672
 673                 if (*activep) {
 674                         if (opcode == oLocalForward)
 675                                 add_local_forward(options, &fwd);
 676                         else if (opcode == oRemoteForward)
 677                                 add_remote_forward(options, &fwd);
 678                 }
 679                 break;
 680
 681         case oDynamicForward:
 682                 arg = strdelim(&s);
 683                 if (!arg || *arg == '\0')
 684                         fatal("%.200s line %d: Missing port argument.",
 685                             filename, linenum);
 686                 memset(&fwd, '\0', sizeof(fwd));
 687                 fwd.connect_host = "socks";
 688                 fwd.listen_host = hpdelim(&arg);
 689                 if (fwd.listen_host == NULL ||
 690                     strlen(fwd.listen_host) >= NI_MAXHOST)
 691                         fatal("%.200s line %d: Bad forwarding specification.",
 692                             filename, linenum);
 693                 if (arg) {
 694                         fwd.listen_port = a2port(arg);
 695                         fwd.listen_host = cleanhostname(fwd.listen_host);
 696                 } else {
 697                         fwd.listen_port = a2port(fwd.listen_host);
 698                         fwd.listen_host = "";
 699                 }
 700                 if (fwd.listen_port == 0)
 701                         fatal("%.200s line %d: Badly formatted port number.",
 702                             filename, linenum);
 703                 if (*activep)
 704                         add_local_forward(options, &fwd);
 705                 break;
 706
 707         case oClearAllForwardings:
 708                 intptr = &options->clear_forwardings;
 709                 goto parse_flag;
 710
 711         case oHost:
 712                 *activep = 0;
 713                 while ((arg = strdelim(&s)) != NULL && *arg != '\0')
 714                         if (match_pattern(host, arg)) {
 715                                 debug("Applying options for %.100s", arg);
 716                                 *activep = 1;
 717                                 break;
 718                         }
 719                 /* Avoid garbage check below, as strdelim is done. */
 720                 return 0;
 721
 722         case oEscapeChar:
 723                 intptr = &options->escape_char;
 724                 arg = strdelim(&s);
 725                 if (!arg || *arg == '\0')
 726                         fatal("%.200s line %d: Missing argument.", filename, linenum);
 727                 if (arg[0] == '^' && arg[2] == 0 &&
 728                     (u_char) arg[1] >= 64 && (u_char) arg[1] < 128)
 729                         value = (u_char) arg[1] & 31;
 730                 else if (strlen(arg) == 1)
 731                         value = (u_char) arg[0];
 732                 else if (strcmp(arg, "none") == 0)
 733                         value = SSH_ESCAPECHAR_NONE;
 734                 else {
 735                         fatal("%.200s line %d: Bad escape character.",
 736                             filename, linenum);
 737                         /* NOTREACHED */
 738                         value = 0;      /* Avoid compiler warning. */
 739                 }
 740                 if (*activep && *intptr == -1)
 741                         *intptr = value;
 742                 break;
 743
 744         case oAddressFamily:
 745                 arg = strdelim(&s);
 746                 intptr = &options->address_family;
 747                 if (strcasecmp(arg, "inet") == 0)
 748                         value = AF_INET;
 749                 else if (strcasecmp(arg, "inet6") == 0)
 750                         value = AF_INET6;
 751                 else if (strcasecmp(arg, "any") == 0)
 752                         value = AF_UNSPEC;
 753                 else
 754                         fatal("Unsupported AddressFamily \"%s\"", arg);
 755                 if (*activep && *intptr == -1)
 756                         *intptr = value;
 757                 break;
 758
 759         case oEnableSSHKeysign:
 760                 intptr = &options->enable_ssh_keysign;
 761                 goto parse_flag;
 762
 763         case oIdentitiesOnly:
 764                 intptr = &options->identities_only;
 765                 goto parse_flag;
 766
 767         case oServerAliveInterval:
 768                 intptr = &options->server_alive_interval;
 769                 goto parse_time;
 770
 771         case oServerAliveCountMax:
 772                 intptr = &options->server_alive_count_max;
 773                 goto parse_int;
 774
 775         case oSendEnv:
 776                 while ((arg = strdelim(&s)) != NULL && *arg != '\0') {
 777                         if (strchr(arg, '=') != NULL)
 778                                 fatal("%s line %d: Invalid environment name.",
 779                                     filename, linenum);
 780                         if (!*activep)
 781                                 continue;
 782                         if (options->num_send_env >= MAX_SEND_ENV)
 783                                 fatal("%s line %d: too many send env.",
 784                                     filename, linenum);
 785                         options->send_env[options->num_send_env++] =
 786                             xstrdup(arg);
 787                 }
 788                 break;
 789
 790         case oControlPath:
 791                 charptr = &options->control_path;
 792                 goto parse_string;
 793
 794         case oControlMaster:
 795                 intptr = &options->control_master;
 796                 goto parse_yesnoask;
 797
 798         case oHashKnownHosts:
 799                 intptr = &options->hash_known_hosts;
 800                 goto parse_flag;
 801
 802         case oDeprecated:
 803                 debug("%s line %d: Deprecated option \"%s\"",
 804                     filename, linenum, keyword);
 805                 return 0;
 806
 807         case oUnsupported:
 808                 error("%s line %d: Unsupported option \"%s\"",
 809                     filename, linenum, keyword);
 810                 return 0;
 811
 812         default:
 813                 fatal("process_config_line: Unimplemented opcode %d", opcode);
 814         }
 815
 816         /* Check that there is no garbage at end of line. */
 817         if ((arg = strdelim(&s)) != NULL && *arg != '\0') {
 818                 fatal("%.200s line %d: garbage at end of line; \"%.200s\".",
 819                      filename, linenum, arg);
 820         }
 821         return 0;
 822 }
 823
 824
 825 /*
 826  * Reads the config file and modifies the options accordingly.  Options
 827  * should already be initialized before this call.  This never returns if
 828  * there is an error.  If the file does not exist, this returns 0.
 829  */
 830
 831 int
 832 read_config_file(const char *filename, const char *host, Options *options,
 833     int checkperm)
 834 {
 835         FILE *f;
 836         char line[1024];
 837         int active, linenum;
 838         int bad_options = 0;
 839
 840         /* Open the file. */
 841         if ((f = fopen(filename, "r")) == NULL)
 842                 return 0;
 843
 844         if (checkperm) {
 845                 struct stat sb;
 846
 847                 if (fstat(fileno(f), &sb) == -1)
 848                         fatal("fstat %s: %s", filename, strerror(errno));
 849                 if (((sb.st_uid != 0 && sb.st_uid != getuid()) ||
 850                     (sb.st_mode & 022) != 0))
 851                         fatal("Bad owner or permissions on %s", filename);
 852         }
 853
 854         debug("Reading configuration data %.200s", filename);
 855
 856         /*
 857          * Mark that we are now processing the options.  This flag is turned
 858          * on/off by Host specifications.
 859          */
 860         active = 1;
 861         linenum = 0;
 862         while (fgets(line, sizeof(line), f)) {
 863                 /* Update line number counter. */
 864                 linenum++;
 865                 if (process_config_line(options, host, line, filename, linenum, &active) != 0)
 866                         bad_options++;
 867         }
 868         fclose(f);
 869         if (bad_options > 0)
 870                 fatal("%s: terminating, %d bad configuration options",
 871                     filename, bad_options);
 872         return 1;
 873 }
 874
 875 /*
 876  * Initializes options to special values that indicate that they have not yet
 877  * been set.  Read_config_file will only set options with this value. Options
 878  * are processed in the following order: command line, user config file,
 879  * system config file.  Last, fill_default_options is called.
 880  */
 881
 882 void
 883 initialize_options(Options * options)
 884 {
 885         memset(options, 'X', sizeof(*options));
 886         options->forward_agent = -1;
 887         options->forward_x11 = -1;
 888         options->forward_x11_trusted = -1;
 889         options->xauth_location = NULL;
 890         options->gateway_ports = -1;
 891         options->use_privileged_port = -1;
 892         options->rsa_authentication = -1;
 893         options->pubkey_authentication = -1;
 894         options->challenge_response_authentication = -1;
 895         options->gss_authentication = -1;
 896         options->gss_deleg_creds = -1;
 897         options->password_authentication = -1;
 898         options->kbd_interactive_authentication = -1;
 899         options->kbd_interactive_devices = NULL;
 900         options->rhosts_rsa_authentication = -1;
 901         options->hostbased_authentication = -1;
 902         options->batch_mode = -1;
 903         options->check_host_ip = -1;
 904         options->strict_host_key_checking = -1;
 905         options->compression = -1;
 906         options->tcp_keep_alive = -1;
 907         options->compression_level = -1;
 908         options->port = -1;
 909         options->address_family = -1;
 910         options->connection_attempts = -1;
 911         options->connection_timeout = -1;
 912         options->number_of_password_prompts = -1;
 913         options->cipher = -1;
 914         options->ciphers = NULL;
 915         options->macs = NULL;
 916         options->hostkeyalgorithms = NULL;
 917         options->protocol = SSH_PROTO_UNKNOWN;
 918         options->num_identity_files = 0;
 919         options->hostname = NULL;
 920         options->host_key_alias = NULL;
 921         options->proxy_command = NULL;
 922         options->user = NULL;
 923         options->escape_char = -1;
 924         options->system_hostfile = NULL;
 925         options->user_hostfile = NULL;
 926         options->system_hostfile2 = NULL;
 927         options->user_hostfile2 = NULL;
 928         options->num_local_forwards = 0;
 929         options->num_remote_forwards = 0;
 930         options->clear_forwardings = -1;
 931         options->log_level = SYSLOG_LEVEL_NOT_SET;
 932         options->preferred_authentications = NULL;
 933         options->bind_address = NULL;
 934         options->smartcard_device = NULL;
 935         options->enable_ssh_keysign = - 1;
 936         options->no_host_authentication_for_localhost = - 1;
 937         options->identities_only = - 1;
 938         options->rekey_limit = - 1;
 939         options->verify_host_key_dns = -1;
 940         options->server_alive_interval = -1;
 941         options->server_alive_count_max = -1;
 942         options->num_send_env = 0;
 943         options->control_path = NULL;
 944         options->control_master = -1;
 945         options->hash_known_hosts = -1;
 946 }
 947
 948 /*
 949  * Called after processing other sources of option data, this fills those
 950  * options for which no value has been specified with their default values.
 951  */
 952
 953 void
 954 fill_default_options(Options * options)
 955 {
 956         int len;
 957
 958         if (options->forward_agent == -1)
 959                 options->forward_agent = 0;
 960         if (options->forward_x11 == -1)
 961                 options->forward_x11 = 0;
 962         if (options->forward_x11_trusted == -1)
 963                 options->forward_x11_trusted = 0;
 964         if (options->xauth_location == NULL)
 965                 options->xauth_location = _PATH_XAUTH;
 966         if (options->gateway_ports == -1)
 967                 options->gateway_ports = 0;
 968         if (options->use_privileged_port == -1)
 969                 options->use_privileged_port = 0;
 970         if (options->rsa_authentication == -1)
 971                 options->rsa_authentication = 1;
 972         if (options->pubkey_authentication == -1)
 973                 options->pubkey_authentication = 1;
 974         if (options->challenge_response_authentication == -1)
 975                 options->challenge_response_authentication = 1;
 976         if (options->gss_authentication == -1)
 977                 options->gss_authentication = 0;
 978         if (options->gss_deleg_creds == -1)
 979                 options->gss_deleg_creds = 0;
 980         if (options->password_authentication == -1)
 981                 options->password_authentication = 1;
 982         if (options->kbd_interactive_authentication == -1)
 983                 options->kbd_interactive_authentication = 1;
 984         if (options->rhosts_rsa_authentication == -1)
 985                 options->rhosts_rsa_authentication = 0;
 986         if (options->hostbased_authentication == -1)
 987                 options->hostbased_authentication = 0;
 988         if (options->batch_mode == -1)
 989                 options->batch_mode = 0;
 990         if (options->check_host_ip == -1)
 991                 options->check_host_ip = 1;
 992         if (options->strict_host_key_checking == -1)
 993                 options->strict_host_key_checking = 2;  /* 2 is default */
 994         if (options->compression == -1)
 995                 options->compression = 0;
 996         if (options->tcp_keep_alive == -1)
 997                 options->tcp_keep_alive = 1;
 998         if (options->compression_level == -1)
 999                 options->compression_level = 6;
1000         if (options->port == -1)
1001                 options->port = 0;      /* Filled in ssh_connect. */
1002         if (options->address_family == -1)
1003                 options->address_family = AF_UNSPEC;
1004         if (options->connection_attempts == -1)
1005                 options->connection_attempts = 1;
1006         if (options->number_of_password_prompts == -1)
1007                 options->number_of_password_prompts = 3;
1008         /* Selected in ssh_login(). */
1009         if (options->cipher == -1)
1010                 options->cipher = SSH_CIPHER_NOT_SET;
1011         /* options->ciphers, default set in myproposals.h */
1012         /* options->macs, default set in myproposals.h */
1013         /* options->hostkeyalgorithms, default set in myproposals.h */
1014         if (options->protocol == SSH_PROTO_UNKNOWN)
1015                 options->protocol = SSH_PROTO_1|SSH_PROTO_2;
1016         if (options->num_identity_files == 0) {
1017                 if (options->protocol & SSH_PROTO_1) {
1018                         len = 2 + strlen(_PATH_SSH_CLIENT_IDENTITY) + 1;
1019                         options->identity_files[options->num_identity_files] =
1020                             xmalloc(len);
1021                         snprintf(options->identity_files[options->num_identity_files++],
1022                             len, "~/%.100s", _PATH_SSH_CLIENT_IDENTITY);
1023                 }
1024                 if (options->protocol & SSH_PROTO_2) {
1025                         len = 2 + strlen(_PATH_SSH_CLIENT_ID_RSA) + 1;
1026                         options->identity_files[options->num_identity_files] =
1027                             xmalloc(len);
1028                         snprintf(options->identity_files[options->num_identity_files++],
1029                             len, "~/%.100s", _PATH_SSH_CLIENT_ID_RSA);
1030
1031                         len = 2 + strlen(_PATH_SSH_CLIENT_ID_DSA) + 1;
1032                         options->identity_files[options->num_identity_files] =
1033                             xmalloc(len);
1034                         snprintf(options->identity_files[options->num_identity_files++],
1035                             len, "~/%.100s", _PATH_SSH_CLIENT_ID_DSA);
1036                 }
1037         }
1038         if (options->escape_char == -1)
1039                 options->escape_char = '~';
1040         if (options->system_hostfile == NULL)
1041                 options->system_hostfile = _PATH_SSH_SYSTEM_HOSTFILE;
1042         if (options->user_hostfile == NULL)
1043                 options->user_hostfile = _PATH_SSH_USER_HOSTFILE;
1044         if (options->system_hostfile2 == NULL)
1045                 options->system_hostfile2 = _PATH_SSH_SYSTEM_HOSTFILE2;
1046         if (options->user_hostfile2 == NULL)
1047                 options->user_hostfile2 = _PATH_SSH_USER_HOSTFILE2;
1048         if (options->log_level == SYSLOG_LEVEL_NOT_SET)
1049                 options->log_level = SYSLOG_LEVEL_INFO;
1050         if (options->clear_forwardings == 1)
1051                 clear_forwardings(options);
1052         if (options->no_host_authentication_for_localhost == - 1)
1053                 options->no_host_authentication_for_localhost = 0;
1054         if (options->identities_only == -1)
1055                 options->identities_only = 0;
1056         if (options->enable_ssh_keysign == -1)
1057                 options->enable_ssh_keysign = 0;
1058         if (options->rekey_limit == -1)
1059                 options->rekey_limit = 0;
1060         if (options->verify_host_key_dns == -1)
1061                 options->verify_host_key_dns = 0;
1062         if (options->server_alive_interval == -1)
1063                 options->server_alive_interval = 0;
1064         if (options->server_alive_count_max == -1)
1065                 options->server_alive_count_max = 3;
1066         if (options->control_master == -1)
1067                 options->control_master = 0;
1068         if (options->hash_known_hosts == -1)
1069                 options->hash_known_hosts = 0;
1070         /* options->proxy_command should not be set by default */
1071         /* options->user will be set in the main program if appropriate */
1072         /* options->hostname will be set in the main program if appropriate */
1073         /* options->host_key_alias should not be set by default */
1074         /* options->preferred_authentications will be set in ssh */
1075 }
1076
1077 /*
1078  * parse_forward
1079  * parses a string containing a port forwarding specification of the form:
1080  *      [listenhost:]listenport:connecthost:connectport
1081  * returns number of arguments parsed or zero on error
1082  */
1083 int
1084 parse_forward(Forward *fwd, const char *fwdspec)
1085 {
1086         int i;
1087         char *p, *cp, *fwdarg[4];
1088
1089         memset(fwd, '\0', sizeof(*fwd));
1090
1091         cp = p = xstrdup(fwdspec);
1092
1093         /* skip leading spaces */
1094         while (*cp && isspace(*cp))
1095                 cp++;
1096
1097         for (i = 0; i < 4; ++i)
1098                 if ((fwdarg[i] = hpdelim(&cp)) == NULL)
1099                         break;
1100
1101         /* Check for trailing garbage in 4-arg case*/
1102         if (cp != NULL)
1103                 i = 0;  /* failure */
1104
1105         switch (i) {
1106         case 3:
1107                 fwd->listen_host = NULL;
1108                 fwd->listen_port = a2port(fwdarg[0]);
1109                 fwd->connect_host = xstrdup(cleanhostname(fwdarg[1]));
1110                 fwd->connect_port = a2port(fwdarg[2]);
1111                 break;
1112
1113         case 4:
1114                 fwd->listen_host = xstrdup(cleanhostname(fwdarg[0]));
1115                 fwd->listen_port = a2port(fwdarg[1]);
1116                 fwd->connect_host = xstrdup(cleanhostname(fwdarg[2]));
1117                 fwd->connect_port = a2port(fwdarg[3]);
1118                 break;
1119         default:
1120                 i = 0; /* failure */
1121         }
1122
1123         xfree(p);
1124
1125         if (fwd->listen_port == 0 && fwd->connect_port == 0)
1126                 goto fail_free;
1127
1128         if (fwd->connect_host != NULL &&
1129             strlen(fwd->connect_host) >= NI_MAXHOST)
1130                 goto fail_free;
1131
1132         return (i);
1133
1134  fail_free:
1135         if (fwd->connect_host != NULL)
1136                 xfree(fwd->connect_host);
1137         if (fwd->listen_host != NULL)
1138                 xfree(fwd->listen_host);
1139         return (0);
1140 }