lib/hdb/keys.c

   1 /*
   2  * Copyright (c) 1997 - 2001, 2003 - 2004 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 "hdb_locl.h"
  35
  36 RCSID("$Id$");
  37
  38 /*
  39  * free all the memory used by (len, keys)
  40  */
  41
  42 void
  43 hdb_free_keys (krb5_context context, int len, Key *keys)
  44 {
  45     int i;
  46
  47     for (i = 0; i < len; i++) {
  48         free(keys[i].mkvno);
  49         keys[i].mkvno = NULL;
  50         if (keys[i].salt != NULL) {
  51             free_Salt(keys[i].salt);
  52             free(keys[i].salt);
  53             keys[i].salt = NULL;
  54         }
  55         krb5_free_keyblock_contents(context, &keys[i].key);
  56     }
  57     free (keys);
  58 }
  59
  60 /*
  61  * for each entry in `default_keys' try to parse it as a sequence
  62  * of etype:salttype:salt, syntax of this if something like:
  63  * [(des|des3|etype):](pw-salt|afs3)[:string], if etype is omitted it
  64  *      means all etypes, and if string is omitted is means the default
  65  * string (for that principal). Additional special values:
  66  *      v5 == pw-salt, and
  67  *      v4 == des:pw-salt:
  68  *      afs or afs3 == des:afs3-salt
  69  */
  70
  71 /* the 3 DES types must be first */
  72 static const krb5_enctype all_etypes[] = {
  73     ETYPE_DES_CBC_MD5,
  74     ETYPE_DES_CBC_MD4,
  75     ETYPE_DES_CBC_CRC,
  76     ETYPE_AES256_CTS_HMAC_SHA1_96,
  77     ETYPE_ARCFOUR_HMAC_MD5,
  78     ETYPE_DES3_CBC_SHA1
  79 };
  80
  81 static krb5_error_code
  82 parse_key_set(krb5_context context, const char *key,
  83               krb5_enctype **ret_enctypes, size_t *ret_num_enctypes,
  84               krb5_salt *salt, krb5_principal principal)
  85 {
  86     const char *p;
  87     char buf[3][256];
  88     int num_buf = 0;
  89     int i, num_enctypes = 0;
  90     krb5_enctype e;
  91     const krb5_enctype *enctypes = NULL;
  92     krb5_error_code ret;
  93
  94     p = key;
  95
  96     *ret_enctypes = NULL;
  97     *ret_num_enctypes = 0;
  98
  99     /* split p in a list of :-separated strings */
 100     for(num_buf = 0; num_buf < 3; num_buf++)
 101         if(strsep_copy(&p, ":", buf[num_buf], sizeof(buf[num_buf])) == -1)
 102             break;
 103
 104     salt->saltvalue.data = NULL;
 105     salt->saltvalue.length = 0;
 106
 107     for(i = 0; i < num_buf; i++) {
 108         if(enctypes == NULL && num_buf > 1) {
 109             /* this might be a etype specifier */
 110             /* XXX there should be a string_to_etypes handling
 111                special cases like `des' and `all' */
 112             if(strcmp(buf[i], "des") == 0) {
 113                 enctypes = all_etypes;
 114                 num_enctypes = 3;
 115             } else if(strcmp(buf[i], "des3") == 0) {
 116                 e = ETYPE_DES3_CBC_SHA1;
 117                 enctypes = &e;
 118                 num_enctypes = 1;
 119             } else {
 120                 ret = krb5_string_to_enctype(context, buf[i], &e);
 121                 if (ret == 0) {
 122                     enctypes = &e;
 123                     num_enctypes = 1;
 124                 } else
 125                     return ret;
 126             }
 127             continue;
 128         }
 129         if(salt->salttype == 0) {
 130             /* interpret string as a salt specifier, if no etype
 131                is set, this sets default values */
 132             /* XXX should perhaps use string_to_salttype, but that
 133                interface sucks */
 134             if(strcmp(buf[i], "pw-salt") == 0) {
 135                 if(enctypes == NULL) {
 136                     enctypes = all_etypes;
 137                     num_enctypes = sizeof(all_etypes)/sizeof(all_etypes[0]);
 138                 }
 139                 salt->salttype = KRB5_PW_SALT;
 140             } else if(strcmp(buf[i], "afs3-salt") == 0) {
 141                 if(enctypes == NULL) {
 142                     enctypes = all_etypes;
 143                     num_enctypes = 3;
 144                 }
 145                 salt->salttype = KRB5_AFS3_SALT;
 146             }
 147             continue;
 148         }
 149
 150         {
 151             /* if there is a final string, use it as the string to
 152                salt with, this is mostly useful with null salt for
 153                v4 compat, and a cell name for afs compat */
 154             salt->saltvalue.data = strdup(buf[i]);
 155             if (salt->saltvalue.data == NULL) {
 156                 krb5_set_error_string(context, "out of memory");
 157                 return ENOMEM;
 158             }
 159             salt->saltvalue.length = strlen(buf[i]);
 160         }
 161     }
 162
 163     if(enctypes == NULL || salt->salttype == 0) {
 164         krb5_set_error_string(context, "bad value for default_keys `%s'", key);
 165         return EINVAL;
 166     }
 167
 168     /* if no salt was specified make up default salt */
 169     if(salt->saltvalue.data == NULL) {
 170         if(salt->salttype == KRB5_PW_SALT)
 171             ret = krb5_get_pw_salt(context, principal, salt);
 172         else if(salt->salttype == KRB5_AFS3_SALT) {
 173             krb5_realm *realm = krb5_princ_realm(context, principal);
 174             salt->saltvalue.data = strdup(*realm);
 175             if(salt->saltvalue.data == NULL) {
 176                 krb5_set_error_string(context, "out of memory while "
 177                                       "parsing salt specifiers");
 178                 return ENOMEM;
 179             }
 180             strlwr(salt->saltvalue.data);
 181             salt->saltvalue.length = strlen(*realm);
 182         }
 183     }
 184
 185     *ret_enctypes = malloc(sizeof(enctypes[0]) * num_enctypes);
 186     if (*ret_enctypes == NULL) {
 187         krb5_free_salt(context, *salt);
 188         krb5_set_error_string(context, "out of memory");
 189         return ENOMEM;
 190     }
 191     memcpy(*ret_enctypes, enctypes, sizeof(enctypes[0]) * num_enctypes);
 192     *ret_num_enctypes = num_enctypes;
 193
 194     return 0;
 195 }
 196
 197 static krb5_error_code
 198 add_enctype_to_key_set(Key **key_set, size_t *nkeyset,
 199                        krb5_enctype enctype, krb5_salt *salt)
 200 {
 201     krb5_error_code ret;
 202     Key key, *tmp;
 203
 204     memset(&key, 0, sizeof(key));
 205
 206     tmp = realloc(*key_set, (*nkeyset + 1) * sizeof((*key_set)[0]));
 207     if (tmp == NULL)
 208         return ENOMEM;
 209
 210     *key_set = tmp;
 211
 212     key.key.keytype = enctype;
 213     key.key.keyvalue.length = 0;
 214     key.key.keyvalue.data = NULL;
 215
 216     if (salt) {
 217         key.salt = malloc(sizeof(*key.salt));
 218         if (key.salt == NULL) {
 219             free_Key(&key);
 220             return ENOMEM;
 221         }
 222
 223         key.salt->type = salt->salttype;
 224         krb5_data_zero (&key.salt->salt);
 225
 226         ret = krb5_data_copy(&key.salt->salt,
 227                              salt->saltvalue.data,
 228                              salt->saltvalue.length);
 229         if (ret) {
 230             free_Key(&key);
 231             return ret;
 232         }
 233     } else
 234         key.salt = NULL;
 235
 236     (*key_set)[*nkeyset] = key;
 237
 238     *nkeyset += 1;
 239
 240     return 0;
 241 }
 242
 243
 244 /*
 245  * Generate the `key_set' from the [kadmin]default_keys statement. If
 246  * `no_salt' is set, salt is not important (and will not be set) since
 247  * it's random keys that is going to be created.
 248  */
 249
 250 krb5_error_code
 251 hdb_generate_key_set(krb5_context context, krb5_principal principal,
 252                      Key **ret_key_set, size_t *nkeyset, int no_salt)
 253 {
 254     char **ktypes, **kp;
 255     krb5_error_code ret;
 256     Key *k, *key_set;
 257     int i, j;
 258     char *default_keytypes[] = {
 259         "des:pw-salt",
 260         "aes256-cts-hmac-sha1-96:pw-salt",
 261         "des3-cbc-sha1:pw-salt",
 262         "arcfour-hmac-md5:pw-salt",
 263         NULL
 264     };
 265
 266     ktypes = krb5_config_get_strings(context, NULL, "kadmin",
 267                                      "default_keys", NULL);
 268     if (ktypes == NULL)
 269         ktypes = default_keytypes;
 270
 271     if (ktypes == NULL)
 272         abort();
 273
 274     *ret_key_set = key_set = NULL;
 275     *nkeyset = 0;
 276
 277     ret = 0;
 278
 279     for(kp = ktypes; kp && *kp; kp++) {
 280         const char *p;
 281         krb5_salt salt;
 282         krb5_enctype *enctypes;
 283         size_t num_enctypes;
 284
 285         p = *kp;
 286         /* check alias */
 287         if(strcmp(p, "v5") == 0)
 288             p = "pw-salt";
 289         else if(strcmp(p, "v4") == 0)
 290             p = "des:pw-salt:";
 291         else if(strcmp(p, "afs") == 0 || strcmp(p, "afs3") == 0)
 292             p = "des:afs3-salt";
 293         else if (strcmp(p, "arcfour-hmac-md5") == 0)
 294             p = "arcfour-hmac-md5:pw-salt";
 295
 296         memset(&salt, 0, sizeof(salt));
 297
 298         ret = parse_key_set(context, p,
 299                             &enctypes, &num_enctypes, &salt, principal);
 300         if (ret) {
 301             krb5_warn(context, ret, "bad value for default_keys `%s'", *kp);
 302             ret = 0;
 303             continue;
 304         }
 305
 306         for (i = 0; i < num_enctypes; i++) {
 307             /* find duplicates */
 308             for (j = 0; j < *nkeyset; j++) {
 309
 310                 k = &key_set[j];
 311
 312                 if (k->key.keytype == enctypes[i]) {
 313                     if (no_salt)
 314                         break;
 315                     if (k->salt == NULL && salt.salttype == KRB5_PW_SALT)
 316                         break;
 317                     if (k->salt->type == salt.salttype &&
 318                         k->salt->salt.length == salt.saltvalue.length &&
 319                         memcmp(k->salt->salt.data, salt.saltvalue.data,
 320                                salt.saltvalue.length) == 0)
 321                         break;
 322                 }
 323             }
 324             /* not a duplicate, lets add it */
 325             if (j == *nkeyset) {
 326                 ret = add_enctype_to_key_set(&key_set, nkeyset, enctypes[i],
 327                                              no_salt ? NULL : &salt);
 328                 if (ret) {
 329                     free(enctypes);
 330                     krb5_free_salt(context, salt);
 331                     goto out;
 332                 }
 333             }
 334         }
 335         free(enctypes);
 336         krb5_free_salt(context, salt);
 337     }
 338
 339     *ret_key_set = key_set;
 340
 341  out:
 342     if (ktypes != default_keytypes)
 343         krb5_config_free_strings(ktypes);
 344
 345     if (ret) {
 346         krb5_warn(context, ret,
 347                   "failed to parse the [kadmin]default_keys values");
 348
 349         for (i = 0; i < *nkeyset; i++)
 350             free_Key(&key_set[i]);
 351         free(key_set);
 352     } else if (*nkeyset == 0) {
 353         krb5_warnx(context,
 354                    "failed to parse any of the [kadmin]default_keys values");
 355         ret = EINVAL; /* XXX */
 356     }
 357
 358     return ret;
 359 }
 360
 361
 362 krb5_error_code
 363 hdb_generate_key_set_password(krb5_context context,
 364                               krb5_principal principal,
 365                               const char *password,
 366                               Key **keys, size_t *num_keys)
 367 {
 368     krb5_error_code ret;
 369     int i;
 370
 371     ret = hdb_generate_key_set(context, principal,
 372                                 keys, num_keys, 0);
 373     if (ret)
 374         return ret;
 375
 376     for (i = 0; i < (*num_keys); i++) {
 377         krb5_salt salt;
 378
 379         salt.salttype = (*keys)[i].salt->type;
 380         salt.saltvalue.length = (*keys)[i].salt->salt.length;
 381         salt.saltvalue.data = (*keys)[i].salt->salt.data;
 382
 383         ret = krb5_string_to_key_salt (context,
 384                                        (*keys)[i].key.keytype,
 385                                        password,
 386                                        salt,
 387                                        &(*keys)[i].key);
 388
 389         if(ret)
 390             break;
 391     }
 392
 393     if(ret) {
 394         hdb_free_keys (context, *num_keys, *keys);
 395         return ret;
 396     }
 397     return ret;
 398 }