lib/krb5/keytab.c

   1 /*
   2  * Copyright (c) 1997 - 2005 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "krb5_locl.h"
  35
  36 RCSID("$Id$");
  37
  38 /*
  39  * Register a new keytab in `ops'
  40  * Return 0 or an error.
  41  */
  42
  43 krb5_error_code KRB5_LIB_FUNCTION
  44 krb5_kt_register(krb5_context context,
  45                  const krb5_kt_ops *ops)
  46 {
  47     struct krb5_keytab_data *tmp;
  48
  49     if (strlen(ops->prefix) > KRB5_KT_PREFIX_MAX_LEN - 1) {
  50         krb5_set_error_string(context, "krb5_kt_register; prefix too long");
  51         return KRB5_KT_BADNAME;
  52     }
  53
  54     tmp = realloc(context->kt_types,
  55                   (context->num_kt_types + 1) * sizeof(*context->kt_types));
  56     if(tmp == NULL) {
  57         krb5_set_error_string(context, "malloc: out of memory");
  58         return ENOMEM;
  59     }
  60     memcpy(&tmp[context->num_kt_types], ops,
  61            sizeof(tmp[context->num_kt_types]));
  62     context->kt_types = tmp;
  63     context->num_kt_types++;
  64     return 0;
  65 }
  66
  67 /*
  68  * Resolve the keytab name (of the form `type:residual') in `name'
  69  * into a keytab in `id'.
  70  * Return 0 or an error
  71  */
  72
  73 krb5_error_code KRB5_LIB_FUNCTION
  74 krb5_kt_resolve(krb5_context context,
  75                 const char *name,
  76                 krb5_keytab *id)
  77 {
  78     krb5_keytab k;
  79     int i;
  80     const char *type, *residual;
  81     size_t type_len;
  82     krb5_error_code ret;
  83
  84     residual = strchr(name, ':');
  85     if(residual == NULL) {
  86         type = "FILE";
  87         type_len = strlen(type);
  88         residual = name;
  89     } else {
  90         type = name;
  91         type_len = residual - name;
  92         residual++;
  93     }
  94
  95     for(i = 0; i < context->num_kt_types; i++) {
  96         if(strncasecmp(type, context->kt_types[i].prefix, type_len) == 0)
  97             break;
  98     }
  99     if(i == context->num_kt_types) {
 100         krb5_set_error_string(context, "unknown keytab type %.*s",
 101                               (int)type_len, type);
 102         return KRB5_KT_UNKNOWN_TYPE;
 103     }
 104
 105     k = malloc (sizeof(*k));
 106     if (k == NULL) {
 107         krb5_set_error_string(context, "malloc: out of memory");
 108         return ENOMEM;
 109     }
 110     memcpy(k, &context->kt_types[i], sizeof(*k));
 111     k->data = NULL;
 112     ret = (*k->resolve)(context, residual, k);
 113     if(ret) {
 114         free(k);
 115         k = NULL;
 116     }
 117     *id = k;
 118     return ret;
 119 }
 120
 121 /*
 122  * copy the name of the default keytab into `name'.
 123  * Return 0 or KRB5_CONFIG_NOTENUFSPACE if `namesize' is too short.
 124  */
 125
 126 krb5_error_code KRB5_LIB_FUNCTION
 127 krb5_kt_default_name(krb5_context context, char *name, size_t namesize)
 128 {
 129     if (strlcpy (name, context->default_keytab, namesize) >= namesize) {
 130         krb5_clear_error_string (context);
 131         return KRB5_CONFIG_NOTENUFSPACE;
 132     }
 133     return 0;
 134 }
 135
 136 /*
 137  * copy the name of the default modify keytab into `name'.
 138  * Return 0 or KRB5_CONFIG_NOTENUFSPACE if `namesize' is too short.
 139  */
 140
 141 krb5_error_code KRB5_LIB_FUNCTION
 142 krb5_kt_default_modify_name(krb5_context context, char *name, size_t namesize)
 143 {
 144     const char *kt = NULL;
 145     if(context->default_keytab_modify == NULL) {
 146         if(strncasecmp(context->default_keytab, "ANY:", 4) != 0)
 147             kt = context->default_keytab;
 148         else {
 149             size_t len = strcspn(context->default_keytab + 4, ",");
 150             if(len >= namesize) {
 151                 krb5_clear_error_string(context);
 152                 return KRB5_CONFIG_NOTENUFSPACE;
 153             }
 154             strlcpy(name, context->default_keytab + 4, namesize);
 155             name[len] = '\0';
 156             return 0;
 157         }
 158     } else
 159         kt = context->default_keytab_modify;
 160     if (strlcpy (name, kt, namesize) >= namesize) {
 161         krb5_clear_error_string (context);
 162         return KRB5_CONFIG_NOTENUFSPACE;
 163     }
 164     return 0;
 165 }
 166
 167 /*
 168  * Set `id' to the default keytab.
 169  * Return 0 or an error.
 170  */
 171
 172 krb5_error_code KRB5_LIB_FUNCTION
 173 krb5_kt_default(krb5_context context, krb5_keytab *id)
 174 {
 175     return krb5_kt_resolve (context, context->default_keytab, id);
 176 }
 177
 178 /*
 179  * Read the key identified by `(principal, vno, enctype)' from the
 180  * keytab in `keyprocarg' (the default if == NULL) into `*key'.
 181  * Return 0 or an error.
 182  */
 183
 184 krb5_error_code KRB5_LIB_FUNCTION
 185 krb5_kt_read_service_key(krb5_context context,
 186                          krb5_pointer keyprocarg,
 187                          krb5_principal principal,
 188                          krb5_kvno vno,
 189                          krb5_enctype enctype,
 190                          krb5_keyblock **key)
 191 {
 192     krb5_keytab keytab;
 193     krb5_keytab_entry entry;
 194     krb5_error_code ret;
 195
 196     if (keyprocarg)
 197         ret = krb5_kt_resolve (context, keyprocarg, &keytab);
 198     else
 199         ret = krb5_kt_default (context, &keytab);
 200
 201     if (ret)
 202         return ret;
 203
 204     ret = krb5_kt_get_entry (context, keytab, principal, vno, enctype, &entry);
 205     krb5_kt_close (context, keytab);
 206     if (ret)
 207         return ret;
 208     ret = krb5_copy_keyblock (context, &entry.keyblock, key);
 209     krb5_kt_free_entry(context, &entry);
 210     return ret;
 211 }
 212
 213 /*
 214  * Return the type of the `keytab' in the string `prefix of length
 215  * `prefixsize'.
 216  */
 217
 218 krb5_error_code KRB5_LIB_FUNCTION
 219 krb5_kt_get_type(krb5_context context,
 220                  krb5_keytab keytab,
 221                  char *prefix,
 222                  size_t prefixsize)
 223 {
 224     strlcpy(prefix, keytab->prefix, prefixsize);
 225     return 0;
 226 }
 227
 228 /*
 229  * Retrieve the name of the keytab `keytab' into `name', `namesize'
 230  * Return 0 or an error.
 231  */
 232
 233 krb5_error_code KRB5_LIB_FUNCTION
 234 krb5_kt_get_name(krb5_context context,
 235                  krb5_keytab keytab,
 236                  char *name,
 237                  size_t namesize)
 238 {
 239     return (*keytab->get_name)(context, keytab, name, namesize);
 240 }
 241
 242 /*
 243  * Retrieve the full name of the keytab `keytab' and store the name in
 244  * `str'. `str' needs to be freed by the caller using free(3).
 245  * Returns 0 or an error. On error, *str is set to NULL.
 246  */
 247
 248 krb5_error_code KRB5_LIB_FUNCTION
 249 krb5_kt_get_full_name(krb5_context context,
 250                       krb5_keytab keytab,
 251                       char **str)
 252 {
 253     char type[KRB5_KT_PREFIX_MAX_LEN];
 254     char name[MAXPATHLEN];
 255     krb5_error_code ret;
 256
 257     *str = NULL;
 258
 259     ret = krb5_kt_get_type(context, keytab, type, sizeof(type));
 260     if (ret)
 261         return ret;
 262
 263     ret = krb5_kt_get_name(context, keytab, name, sizeof(name));
 264     if (ret)
 265         return ret;
 266
 267     if (asprintf(str, "%s:%s", type, name) == -1) {
 268         krb5_set_error_string(context, "malloc - out of memory");
 269         *str = NULL;
 270         return ENOMEM;
 271     }
 272
 273     return 0;
 274 }
 275
 276 /*
 277  * Finish using the keytab in `id'.  All resources will be released,
 278  * even on errors.  Return 0 or an error.
 279  */
 280
 281 krb5_error_code KRB5_LIB_FUNCTION
 282 krb5_kt_close(krb5_context context,
 283               krb5_keytab id)
 284 {
 285     krb5_error_code ret;
 286
 287     ret = (*id->close)(context, id);
 288     memset(id, 0, sizeof(*id));
 289     free(id);
 290     return ret;
 291 }
 292
 293 /*
 294  * Compare `entry' against `principal, vno, enctype'.
 295  * Any of `principal, vno, enctype' might be 0 which acts as a wildcard.
 296  * Return TRUE if they compare the same, FALSE otherwise.
 297  */
 298
 299 krb5_boolean KRB5_LIB_FUNCTION
 300 krb5_kt_compare(krb5_context context,
 301                 krb5_keytab_entry *entry,
 302                 krb5_const_principal principal,
 303                 krb5_kvno vno,
 304                 krb5_enctype enctype)
 305 {
 306     if(principal != NULL &&
 307        !krb5_principal_compare(context, entry->principal, principal))
 308         return FALSE;
 309     if(vno && vno != entry->vno)
 310         return FALSE;
 311     if(enctype && enctype != entry->keyblock.keytype)
 312         return FALSE;
 313     return TRUE;
 314 }
 315
 316 /*
 317  * Retrieve the keytab entry for `principal, kvno, enctype' into `entry'
 318  * from the keytab `id'.
 319  * kvno == 0 is a wildcard and gives the keytab with the highest vno.
 320  * Return 0 or an error.
 321  */
 322
 323 krb5_error_code KRB5_LIB_FUNCTION
 324 krb5_kt_get_entry(krb5_context context,
 325                   krb5_keytab id,
 326                   krb5_const_principal principal,
 327                   krb5_kvno kvno,
 328                   krb5_enctype enctype,
 329                   krb5_keytab_entry *entry)
 330 {
 331     krb5_keytab_entry tmp;
 332     krb5_error_code ret;
 333     krb5_kt_cursor cursor;
 334
 335     if(id->get)
 336         return (*id->get)(context, id, principal, kvno, enctype, entry);
 337
 338     ret = krb5_kt_start_seq_get (context, id, &cursor);
 339     if (ret) {
 340         krb5_clear_error_string(context);
 341         return KRB5_KT_NOTFOUND; /* XXX i.e. file not found */
 342     }
 343
 344     entry->vno = 0;
 345     while (krb5_kt_next_entry(context, id, &tmp, &cursor) == 0) {
 346         if (krb5_kt_compare(context, &tmp, principal, 0, enctype)) {
 347             /* the file keytab might only store the lower 8 bits of
 348                the kvno, so only compare those bits */
 349             if (kvno == tmp.vno
 350                 || (tmp.vno < 256 && kvno % 256 == tmp.vno)) {
 351                 krb5_kt_copy_entry_contents (context, &tmp, entry);
 352                 krb5_kt_free_entry (context, &tmp);
 353                 krb5_kt_end_seq_get(context, id, &cursor);
 354                 return 0;
 355             } else if (kvno == 0 && tmp.vno > entry->vno) {
 356                 if (entry->vno)
 357                     krb5_kt_free_entry (context, entry);
 358                 krb5_kt_copy_entry_contents (context, &tmp, entry);
 359             }
 360         }
 361         krb5_kt_free_entry(context, &tmp);
 362     }
 363     krb5_kt_end_seq_get (context, id, &cursor);
 364     if (entry->vno) {
 365         return 0;
 366     } else {
 367         char princ[256], kvno_str[25], *kt_name;
 368         char *enctype_str = NULL;
 369
 370         krb5_unparse_name_fixed (context, principal, princ, sizeof(princ));
 371         krb5_kt_get_full_name (context, id, &kt_name);
 372         krb5_enctype_to_string(context, enctype, &enctype_str);
 373
 374         if (kvno)
 375             snprintf(kvno_str, sizeof(kvno_str), "(kvno %d)", kvno);
 376         else
 377             kvno_str[0] = '\0';
 378
 379         krb5_set_error_string (context,
 380                                "Failed to find %s%s in keytab %s (%s)",
 381                                princ,
 382                                kvno_str,
 383                                kt_name ? kt_name : "unknown keytab",
 384                                enctype_str ? enctype_str : "unknown enctype");
 385         free(kt_name);
 386         free(enctype_str);
 387         return KRB5_KT_NOTFOUND;
 388     }
 389 }
 390
 391 /*
 392  * Copy the contents of `in' into `out'.
 393  * Return 0 or an error.  */
 394
 395 krb5_error_code KRB5_LIB_FUNCTION
 396 krb5_kt_copy_entry_contents(krb5_context context,
 397                             const krb5_keytab_entry *in,
 398                             krb5_keytab_entry *out)
 399 {
 400     krb5_error_code ret;
 401
 402     memset(out, 0, sizeof(*out));
 403     out->vno = in->vno;
 404
 405     ret = krb5_copy_principal (context, in->principal, &out->principal);
 406     if (ret)
 407         goto fail;
 408     ret = krb5_copy_keyblock_contents (context,
 409                                        &in->keyblock,
 410                                        &out->keyblock);
 411     if (ret)
 412         goto fail;
 413     out->timestamp = in->timestamp;
 414     return 0;
 415 fail:
 416     krb5_kt_free_entry (context, out);
 417     return ret;
 418 }
 419
 420 /*
 421  * Free the contents of `entry'.
 422  */
 423
 424 krb5_error_code KRB5_LIB_FUNCTION
 425 krb5_kt_free_entry(krb5_context context,
 426                    krb5_keytab_entry *entry)
 427 {
 428     krb5_free_principal (context, entry->principal);
 429     krb5_free_keyblock_contents (context, &entry->keyblock);
 430     memset(entry, 0, sizeof(*entry));
 431     return 0;
 432 }
 433
 434 /*
 435  * Set `cursor' to point at the beginning of `id'.
 436  * Return 0 or an error.
 437  */
 438
 439 krb5_error_code KRB5_LIB_FUNCTION
 440 krb5_kt_start_seq_get(krb5_context context,
 441                       krb5_keytab id,
 442                       krb5_kt_cursor *cursor)
 443 {
 444     if(id->start_seq_get == NULL) {
 445         krb5_set_error_string(context,
 446                               "start_seq_get is not supported in the %s "
 447                               " keytab", id->prefix);
 448         return HEIM_ERR_OPNOTSUPP;
 449     }
 450     return (*id->start_seq_get)(context, id, cursor);
 451 }
 452
 453 /*
 454  * Get the next entry from `id' pointed to by `cursor' and advance the
 455  * `cursor'.
 456  * Return 0 or an error.
 457  */
 458
 459 krb5_error_code KRB5_LIB_FUNCTION
 460 krb5_kt_next_entry(krb5_context context,
 461                    krb5_keytab id,
 462                    krb5_keytab_entry *entry,
 463                    krb5_kt_cursor *cursor)
 464 {
 465     if(id->next_entry == NULL) {
 466         krb5_set_error_string(context,
 467                               "next_entry is not supported in the %s "
 468                               " keytab", id->prefix);
 469         return HEIM_ERR_OPNOTSUPP;
 470     }
 471     return (*id->next_entry)(context, id, entry, cursor);
 472 }
 473
 474 /*
 475  * Release all resources associated with `cursor'.
 476  */
 477
 478 krb5_error_code KRB5_LIB_FUNCTION
 479 krb5_kt_end_seq_get(krb5_context context,
 480                     krb5_keytab id,
 481                     krb5_kt_cursor *cursor)
 482 {
 483     if(id->end_seq_get == NULL) {
 484         krb5_set_error_string(context,
 485                               "end_seq_get is not supported in the %s "
 486                               " keytab", id->prefix);
 487         return HEIM_ERR_OPNOTSUPP;
 488     }
 489     return (*id->end_seq_get)(context, id, cursor);
 490 }
 491
 492 /*
 493  * Add the entry in `entry' to the keytab `id'.
 494  * Return 0 or an error.
 495  */
 496
 497 krb5_error_code KRB5_LIB_FUNCTION
 498 krb5_kt_add_entry(krb5_context context,
 499                   krb5_keytab id,
 500                   krb5_keytab_entry *entry)
 501 {
 502     if(id->add == NULL) {
 503         krb5_set_error_string(context, "Add is not supported in the %s keytab",
 504                               id->prefix);
 505         return KRB5_KT_NOWRITE;
 506     }
 507     entry->timestamp = time(NULL);
 508     return (*id->add)(context, id,entry);
 509 }
 510
 511 /*
 512  * Remove the entry `entry' from the keytab `id'.
 513  * Return 0 or an error.
 514  */
 515
 516 krb5_error_code KRB5_LIB_FUNCTION
 517 krb5_kt_remove_entry(krb5_context context,
 518                      krb5_keytab id,
 519                      krb5_keytab_entry *entry)
 520 {
 521     if(id->remove == NULL) {
 522         krb5_set_error_string(context,
 523                               "Remove is not supported in the %s keytab",
 524                               id->prefix);
 525         return KRB5_KT_NOWRITE;
 526     }
 527     return (*id->remove)(context, id, entry);
 528 }