lib/hdb/keys.c

   1
   2 /*
   3  * Copyright (c) 1997 - 2011 Kungliga Tekniska Högskolan
   4  * (Royal Institute of Technology, Stockholm, Sweden).
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  *
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * 3. Neither the name of the Institute nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include "hdb_locl.h"
  36
  37 /*
  38  * free all the memory used by (len, keys)
  39  */
  40
  41 void
  42 hdb_free_keys(krb5_context context, int len, Key *keys)
  43 {
  44     size_t i;
  45
  46     for (i = 0; i < len; i++) {
  47         free(keys[i].mkvno);
  48         keys[i].mkvno = NULL;
  49         if (keys[i].salt != NULL) {
  50             free_Salt(keys[i].salt);
  51             free(keys[i].salt);
  52             keys[i].salt = NULL;
  53         }
  54         krb5_free_keyblock_contents(context, &keys[i].key);
  55     }
  56     free (keys);
  57 }
  58
  59 /*
  60  * for each entry in `default_keys' try to parse it as a sequence
  61  * of etype:salttype:salt, syntax of this if something like:
  62  * [(des|des3|etype):](pw-salt|afs3)[:string], if etype is omitted it
  63  *      means all etypes, and if string is omitted is means the default
  64  * string (for that principal). Additional special values:
  65  *      v5 == pw-salt, and
  66  *      v4 == des:pw-salt:
  67  *      afs or afs3 == des:afs3-salt
  68  */
  69
  70 static const krb5_enctype des_etypes[] = {
  71     KRB5_ENCTYPE_DES_CBC_MD5,
  72     KRB5_ENCTYPE_DES_CBC_MD4,
  73     KRB5_ENCTYPE_DES_CBC_CRC
  74 };
  75
  76 static const krb5_enctype all_etypes[] = {
  77     KRB5_ENCTYPE_AES256_CTS_HMAC_SHA1_96,
  78     KRB5_ENCTYPE_ARCFOUR_HMAC_MD5,
  79     KRB5_ENCTYPE_DES3_CBC_SHA1
  80 };
  81
  82 static krb5_error_code
  83 parse_key_set(krb5_context context, const char *key,
  84               krb5_enctype **ret_enctypes, size_t *ret_num_enctypes,
  85               krb5_salt *salt, krb5_principal principal)
  86 {
  87     const char *p;
  88     char buf[3][256];
  89     int num_buf = 0;
  90     int i, num_enctypes = 0;
  91     krb5_enctype e;
  92     const krb5_enctype *enctypes = NULL;
  93     krb5_error_code ret;
  94
  95     p = key;
  96
  97     *ret_enctypes = NULL;
  98     *ret_num_enctypes = 0;
  99
 100     /* split p in a list of :-separated strings */
 101     for(num_buf = 0; num_buf < 3; num_buf++)
 102         if(strsep_copy(&p, ":", buf[num_buf], sizeof(buf[num_buf])) == -1)
 103             break;
 104
 105     salt->saltvalue.data = NULL;
 106     salt->saltvalue.length = 0;
 107
 108     for(i = 0; i < num_buf; i++) {
 109         if(enctypes == NULL && num_buf > 1) {
 110             /* this might be a etype specifier */
 111             /* XXX there should be a string_to_etypes handling
 112                special cases like `des' and `all' */
 113             if(strcmp(buf[i], "des") == 0) {
 114                 enctypes = des_etypes;
 115                 num_enctypes = sizeof(des_etypes)/sizeof(des_etypes[0]);
 116             } else if(strcmp(buf[i], "des3") == 0) {
 117                 e = KRB5_ENCTYPE_DES3_CBC_SHA1;
 118                 enctypes = &e;
 119                 num_enctypes = 1;
 120             } else {
 121                 ret = krb5_string_to_enctype(context, buf[i], &e);
 122                 if (ret == 0) {
 123                     enctypes = &e;
 124                     num_enctypes = 1;
 125                 } else
 126                     return ret;
 127             }
 128             continue;
 129         }
 130         if(salt->salttype == 0) {
 131             /* interpret string as a salt specifier, if no etype
 132                is set, this sets default values */
 133             /* XXX should perhaps use string_to_salttype, but that
 134                interface sucks */
 135             if(strcmp(buf[i], "pw-salt") == 0) {
 136                 if(enctypes == NULL) {
 137                     enctypes = all_etypes;
 138                     num_enctypes = sizeof(all_etypes)/sizeof(all_etypes[0]);
 139                 }
 140                 salt->salttype = KRB5_PW_SALT;
 141             } else if(strcmp(buf[i], "afs3-salt") == 0) {
 142                 if(enctypes == NULL) {
 143                     enctypes = des_etypes;
 144                     num_enctypes = sizeof(des_etypes)/sizeof(des_etypes[0]);
 145                 }
 146                 salt->salttype = KRB5_AFS3_SALT;
 147             }
 148             continue;
 149         }
 150
 151         {
 152             /* if there is a final string, use it as the string to
 153                salt with, this is mostly useful with null salt for
 154                v4 compat, and a cell name for afs compat */
 155             salt->saltvalue.data = strdup(buf[i]);
 156             if (salt->saltvalue.data == NULL) {
 157                 krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
 158                 return ENOMEM;
 159             }
 160             salt->saltvalue.length = strlen(buf[i]);
 161         }
 162     }
 163
 164     if(enctypes == NULL || salt->salttype == 0) {
 165         krb5_set_error_message(context, EINVAL, "bad value for default_keys `%s'", key);
 166         return EINVAL;
 167     }
 168
 169     /* if no salt was specified make up default salt */
 170     if(salt->saltvalue.data == NULL) {
 171         if(salt->salttype == KRB5_PW_SALT)
 172             ret = krb5_get_pw_salt(context, principal, salt);
 173         else if(salt->salttype == KRB5_AFS3_SALT) {
 174             krb5_const_realm realm = krb5_principal_get_realm(context, principal);
 175             salt->saltvalue.data = strdup(realm);
 176             if(salt->saltvalue.data == NULL) {
 177                 krb5_set_error_message(context, ENOMEM,
 178                                        "out of memory while "
 179                                        "parsing salt specifiers");
 180                 return ENOMEM;
 181             }
 182             strlwr(salt->saltvalue.data);
 183             salt->saltvalue.length = strlen(realm);
 184         }
 185     }
 186
 187     *ret_enctypes = malloc(sizeof(enctypes[0]) * num_enctypes);
 188     if (*ret_enctypes == NULL) {
 189         krb5_free_salt(context, *salt);
 190         krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
 191         return ENOMEM;
 192     }
 193     memcpy(*ret_enctypes, enctypes, sizeof(enctypes[0]) * num_enctypes);
 194     *ret_num_enctypes = num_enctypes;
 195
 196     return 0;
 197 }
 198
 199
 200 /**
 201  * This function adds an HDB entry's current keyset to the entry's key
 202  * history.  The current keyset is left alone; the caller is responsible
 203  * for freeing it.
 204  *
 205  * @param context   Context
 206  * @param entry     HDB entry
 207  */
 208 krb5_error_code
 209 hdb_add_current_keys_to_history(krb5_context context, hdb_entry *entry)
 210 {
 211     krb5_boolean replace = FALSE;
 212     krb5_error_code ret;
 213     HDB_extension *ext;
 214     hdb_keyset newkeyset;
 215     time_t newtime;
 216
 217     if (entry->keys.len == 0)
 218         return 0; /* nothing to do */
 219
 220     ext = hdb_find_extension(entry, choice_HDB_extension_data_hist_keys);
 221     if (ext == NULL) {
 222         replace = TRUE;
 223         ext = calloc(1, sizeof (*ext));
 224         if (ext == NULL)
 225             return krb5_enomem(context);
 226
 227         ext->data.element = choice_HDB_extension_data_hist_keys;
 228     }
 229
 230     /*
 231      * Copy in newest old keyset
 232      */
 233     ret = hdb_entry_get_pw_change_time(entry, &newtime);
 234     if (ret)
 235         goto out;
 236
 237     memset(&newkeyset, 0, sizeof(newkeyset));
 238     newkeyset.keys = entry->keys;
 239     newkeyset.kvno = entry->kvno;
 240     newkeyset.set_time = &newtime;
 241
 242     ret = add_HDB_Ext_KeySet(&ext->data.u.hist_keys, &newkeyset);
 243     if (ret)
 244         goto out;
 245
 246     if (replace) {
 247         /* hdb_replace_extension() deep-copies ext; what a waste */
 248         ret = hdb_replace_extension(context, entry, ext);
 249         if (ret)
 250             goto out;
 251     }
 252
 253  out:
 254     if (replace && ext) {
 255         free_HDB_extension(ext);
 256         free(ext);
 257     }
 258     return ret;
 259 }
 260
 261 /**
 262  * This function adds a key to an HDB entry's key history.
 263  *
 264  * @param context   Context
 265  * @param entry     HDB entry
 266  * @param kvno      Key version number of the key to add to the history
 267  * @param key       The Key to add
 268  */
 269 krb5_error_code
 270 hdb_add_history_key(krb5_context context, hdb_entry *entry, krb5_kvno kvno, Key *key)
 271 {
 272     size_t i;
 273     hdb_keyset keyset;
 274     HDB_Ext_KeySet *hist_keys;
 275     HDB_extension ext;
 276     HDB_extension *extp;
 277     krb5_error_code ret;
 278
 279     memset(&keyset, 0, sizeof (keyset));
 280     memset(&ext, 0, sizeof (ext));
 281
 282     extp = hdb_find_extension(entry, choice_HDB_extension_data_hist_keys);
 283     if (extp == NULL) {
 284         ext.data.element = choice_HDB_extension_data_hist_keys;
 285         extp = &ext;
 286     }
 287
 288     hist_keys = &extp->data.u.hist_keys;
 289
 290     for (i = 0; i < hist_keys->len; i++) {
 291         if (hist_keys->val[i].kvno == kvno) {
 292             ret = add_Keys(&hist_keys->val[i].keys, key);
 293             goto out;
 294         }
 295     }
 296
 297     keyset.kvno = kvno;
 298     ret = add_Keys(&keyset.keys, key);
 299     if (ret)
 300         goto out;
 301     ret = add_HDB_Ext_KeySet(hist_keys, &keyset);
 302     if (ret)
 303         goto out;
 304     if (extp == &ext) {
 305         ret = hdb_replace_extension(context, entry, &ext);
 306         if (ret)
 307             goto out;
 308     }
 309
 310 out:
 311     free_hdb_keyset(&keyset);
 312     free_HDB_extension(&ext);
 313     return ret;
 314 }
 315
 316
 317 /**
 318  * This function changes an hdb_entry's kvno, swapping the current key
 319  * set with a historical keyset.  If no historical keys are found then
 320  * an error is returned (the caller can still set entry->kvno directly).
 321  *
 322  * @param context       krb5_context
 323  * @param new_kvno      New kvno for the entry
 324  * @param entry         hdb_entry to modify
 325  */
 326 krb5_error_code
 327 hdb_change_kvno(krb5_context context, krb5_kvno new_kvno, hdb_entry *entry)
 328 {
 329     HDB_extension ext;
 330     HDB_extension *extp;
 331     hdb_keyset keyset;
 332     HDB_Ext_KeySet *hist_keys;
 333     size_t i;
 334     int found = 0;
 335     krb5_error_code ret;
 336
 337     if (entry->kvno == new_kvno)
 338         return 0;
 339
 340     extp = hdb_find_extension(entry, choice_HDB_extension_data_hist_keys);
 341     if (extp == NULL) {
 342         memset(&ext, 0, sizeof (ext));
 343         ext.data.element = choice_HDB_extension_data_hist_keys;
 344         extp = &ext;
 345     }
 346
 347     memset(&keyset, 0, sizeof (keyset));
 348     hist_keys = &extp->data.u.hist_keys;
 349     for (i = 0; i < hist_keys->len; i++) {
 350         if (hist_keys->val[i].kvno == new_kvno) {
 351             found = 1;
 352             ret = copy_hdb_keyset(&hist_keys->val[i], &keyset);
 353             if (ret)
 354                 goto out;
 355             ret = remove_HDB_Ext_KeySet(hist_keys, i);
 356             if (ret)
 357                 goto out;
 358             break;
 359         }
 360     }
 361
 362     if (!found)
 363         return HDB_ERR_KVNO_NOT_FOUND;
 364
 365     ret = hdb_add_current_keys_to_history(context, entry);
 366     if (ret)
 367         goto out;
 368
 369     /* Note: we do nothing with keyset.set_time */
 370     entry->kvno = new_kvno;
 371     entry->keys = keyset.keys; /* shortcut */
 372     memset(&keyset.keys, 0, sizeof (keyset.keys));
 373
 374 out:
 375     free_hdb_keyset(&keyset);
 376     return ret;
 377 }
 378
 379
 380 static krb5_error_code
 381 add_enctype_to_key_set(Key **key_set, size_t *nkeyset,
 382                        krb5_enctype enctype, krb5_salt *salt)
 383 {
 384     krb5_error_code ret;
 385     Key key, *tmp;
 386
 387     memset(&key, 0, sizeof(key));
 388
 389     tmp = realloc(*key_set, (*nkeyset + 1) * sizeof((*key_set)[0]));
 390     if (tmp == NULL)
 391         return ENOMEM;
 392
 393     *key_set = tmp;
 394
 395     key.key.keytype = enctype;
 396     key.key.keyvalue.length = 0;
 397     key.key.keyvalue.data = NULL;
 398
 399     if (salt) {
 400         key.salt = calloc(1, sizeof(*key.salt));
 401         if (key.salt == NULL) {
 402             free_Key(&key);
 403             return ENOMEM;
 404         }
 405
 406         key.salt->type = salt->salttype;
 407         krb5_data_zero (&key.salt->salt);
 408
 409         ret = krb5_data_copy(&key.salt->salt,
 410                              salt->saltvalue.data,
 411                              salt->saltvalue.length);
 412         if (ret) {
 413             free_Key(&key);
 414             return ret;
 415         }
 416     } else
 417         key.salt = NULL;
 418
 419     (*key_set)[*nkeyset] = key;
 420
 421     *nkeyset += 1;
 422
 423     return 0;
 424 }
 425
 426
 427 static
 428 krb5_error_code
 429 ks_tuple2str(krb5_context context, int n_ks_tuple,
 430              krb5_key_salt_tuple *ks_tuple, char ***ks_tuple_strs)
 431 {
 432         size_t i;
 433         char **ksnames;
 434         char *ename, *sname;
 435         krb5_error_code rc = KRB5_PROG_ETYPE_NOSUPP;
 436
 437         *ks_tuple_strs = NULL;
 438         if (n_ks_tuple < 1)
 439                 return 0;
 440
 441         if ((ksnames = calloc(n_ks_tuple, sizeof (*ksnames))) == NULL)
 442                 return (errno);
 443
 444         for (i = 0; i < n_ks_tuple; i++) {
 445             if (krb5_enctype_to_string(context, ks_tuple[i].ks_enctype, &ename))
 446                 goto out;
 447             if (krb5_salttype_to_string(context, ks_tuple[i].ks_enctype,
 448                                         ks_tuple[i].ks_salttype, &sname))
 449                 goto out;
 450
 451             if (asprintf(&ksnames[i], "%s:%s", ename, sname) == -1) {
 452                     rc = errno;
 453                     free(ename);
 454                     free(sname);
 455                     goto out;
 456             }
 457             free(ename);
 458             free(sname);
 459         }
 460
 461         *ks_tuple_strs = ksnames;
 462         rc = 0;
 463
 464 out:
 465         for (i = 0; i < n_ks_tuple; i++)
 466                 free(ksnames[i]);
 467         free(ksnames);
 468         return (rc);
 469 }
 470
 471 /*
 472  * Generate the `key_set' from the [kadmin]default_keys statement. If
 473  * `no_salt' is set, salt is not important (and will not be set) since
 474  * it's random keys that is going to be created.
 475  */
 476
 477 krb5_error_code
 478 hdb_generate_key_set(krb5_context context, krb5_principal principal,
 479                      int n_ks_tuple, krb5_key_salt_tuple *ks_tuple,
 480                      Key **ret_key_set, size_t *nkeyset, int no_salt)
 481 {
 482     char **ktypes = NULL;
 483     char **kp;
 484     krb5_error_code ret;
 485     Key *k, *key_set;
 486     size_t i, j;
 487     char **ks_tuple_strs;
 488     static const char *default_keytypes[] = {
 489         "aes256-cts-hmac-sha1-96:pw-salt",
 490         "des3-cbc-sha1:pw-salt",
 491         "arcfour-hmac-md5:pw-salt",
 492         NULL
 493     };
 494
 495     if ((ret = ks_tuple2str(context, n_ks_tuple, ks_tuple, &ks_tuple_strs)))
 496             return ret;
 497
 498     if (ks_tuple_strs == NULL)
 499         ktypes = krb5_config_get_strings(context, NULL, "kadmin",
 500                                          "default_keys", NULL);
 501     if (ktypes == NULL)
 502         ktypes = (char **)(intptr_t)default_keytypes;
 503
 504     *ret_key_set = key_set = NULL;
 505     *nkeyset = 0;
 506
 507     for(kp = ktypes; kp && *kp; kp++) {
 508         const char *p;
 509         krb5_salt salt;
 510         krb5_enctype *enctypes;
 511         size_t num_enctypes;
 512
 513         p = *kp;
 514         /* check alias */
 515         if(strcmp(p, "v5") == 0)
 516             p = "pw-salt";
 517         else if(strcmp(p, "v4") == 0)
 518             p = "des:pw-salt:";
 519         else if(strcmp(p, "afs") == 0 || strcmp(p, "afs3") == 0)
 520             p = "des:afs3-salt";
 521         else if (strcmp(p, "arcfour-hmac-md5") == 0)
 522             p = "arcfour-hmac-md5:pw-salt";
 523
 524         memset(&salt, 0, sizeof(salt));
 525
 526         ret = parse_key_set(context, p,
 527                             &enctypes, &num_enctypes, &salt, principal);
 528         if (ret) {
 529             krb5_warn(context, ret, "bad value for default_keys `%s'", *kp);
 530             ret = 0;
 531             continue;
 532         }
 533
 534         for (i = 0; i < num_enctypes; i++) {
 535             /* find duplicates */
 536             for (j = 0; j < *nkeyset; j++) {
 537
 538                 k = &key_set[j];
 539
 540                 if (k->key.keytype == enctypes[i]) {
 541                     if (no_salt)
 542                         break;
 543                     if (k->salt == NULL && salt.salttype == KRB5_PW_SALT)
 544                         break;
 545                     if (k->salt->type == salt.salttype &&
 546                         k->salt->salt.length == salt.saltvalue.length &&
 547                         memcmp(k->salt->salt.data, salt.saltvalue.data,
 548                                salt.saltvalue.length) == 0)
 549                         break;
 550                 }
 551             }
 552             /* not a duplicate, lets add it */
 553             if (j == *nkeyset) {
 554                 ret = add_enctype_to_key_set(&key_set, nkeyset, enctypes[i],
 555                                              no_salt ? NULL : &salt);
 556                 if (ret) {
 557                     free(enctypes);
 558                     krb5_free_salt(context, salt);
 559                     goto out;
 560                 }
 561             }
 562         }
 563         free(enctypes);
 564         krb5_free_salt(context, salt);
 565     }
 566
 567     *ret_key_set = key_set;
 568
 569  out:
 570     if (ktypes != (char **)(intptr_t)default_keytypes)
 571         krb5_config_free_strings(ktypes);
 572
 573     if (ret) {
 574         krb5_warn(context, ret,
 575                   "failed to parse the [kadmin]default_keys values");
 576
 577         for (i = 0; i < *nkeyset; i++)
 578             free_Key(&key_set[i]);
 579         free(key_set);
 580     } else if (*nkeyset == 0) {
 581         krb5_warnx(context,
 582                    "failed to parse any of the [kadmin]default_keys values");
 583         ret = EINVAL; /* XXX */
 584     }
 585
 586     return ret;
 587 }
 588
 589
 590 krb5_error_code
 591 hdb_generate_key_set_password(krb5_context context,
 592                               krb5_principal principal,
 593                               const char *password,
 594                               Key **keys, size_t *num_keys)
 595 {
 596     krb5_error_code ret;
 597     size_t i;
 598
 599     ret = hdb_generate_key_set(context, principal, 0, NULL,
 600                                 keys, num_keys, 0);
 601     if (ret)
 602         return ret;
 603
 604     for (i = 0; i < (*num_keys); i++) {
 605         krb5_salt salt;
 606
 607         salt.salttype = (*keys)[i].salt->type;
 608         salt.saltvalue.length = (*keys)[i].salt->salt.length;
 609         salt.saltvalue.data = (*keys)[i].salt->salt.data;
 610
 611         ret = krb5_string_to_key_salt (context,
 612                                        (*keys)[i].key.keytype,
 613                                        password,
 614                                        salt,
 615                                        &(*keys)[i].key);
 616
 617         if(ret)
 618             break;
 619     }
 620
 621     if(ret) {
 622         hdb_free_keys (context, *num_keys, *keys);
 623         return ret;
 624     }
 625     return ret;
 626 }