lib/hdb/keys.c

   1
   2 /*
   3  * Copyright (c) 1997 - 2001, 2003 - 2004 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     int 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     ETYPE_DES_CBC_MD5,
  72     ETYPE_DES_CBC_MD4,
  73     ETYPE_DES_CBC_CRC
  74 };
  75
  76 static const krb5_enctype all_etypes[] = {
  77     ETYPE_AES256_CTS_HMAC_SHA1_96,
  78     ETYPE_ARCFOUR_HMAC_MD5,
  79     ETYPE_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 = ETYPE_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 static krb5_error_code
 200 add_enctype_to_key_set(Key **key_set, size_t *nkeyset,
 201                        krb5_enctype enctype, krb5_salt *salt)
 202 {
 203     krb5_error_code ret;
 204     Key key, *tmp;
 205
 206     memset(&key, 0, sizeof(key));
 207
 208     tmp = realloc(*key_set, (*nkeyset + 1) * sizeof((*key_set)[0]));
 209     if (tmp == NULL)
 210         return ENOMEM;
 211
 212     *key_set = tmp;
 213
 214     key.key.keytype = enctype;
 215     key.key.keyvalue.length = 0;
 216     key.key.keyvalue.data = NULL;
 217
 218     if (salt) {
 219         key.salt = calloc(1, sizeof(*key.salt));
 220         if (key.salt == NULL) {
 221             free_Key(&key);
 222             return ENOMEM;
 223         }
 224
 225         key.salt->type = salt->salttype;
 226         krb5_data_zero (&key.salt->salt);
 227
 228         ret = krb5_data_copy(&key.salt->salt,
 229                              salt->saltvalue.data,
 230                              salt->saltvalue.length);
 231         if (ret) {
 232             free_Key(&key);
 233             return ret;
 234         }
 235     } else
 236         key.salt = NULL;
 237
 238     (*key_set)[*nkeyset] = key;
 239
 240     *nkeyset += 1;
 241
 242     return 0;
 243 }
 244
 245
 246 /*
 247  * Generate the `key_set' from the [kadmin]default_keys statement. If
 248  * `no_salt' is set, salt is not important (and will not be set) since
 249  * it's random keys that is going to be created.
 250  */
 251
 252 krb5_error_code
 253 hdb_generate_key_set(krb5_context context, krb5_principal principal,
 254                      Key **ret_key_set, size_t *nkeyset, int no_salt)
 255 {
 256     char **ktypes, **kp;
 257     krb5_error_code ret;
 258     Key *k, *key_set;
 259     int i, j;
 260     char *default_keytypes[] = {
 261         "aes256-cts-hmac-sha1-96:pw-salt",
 262         "des3-cbc-sha1:pw-salt",
 263         "arcfour-hmac-md5:pw-salt",
 264         NULL
 265     };
 266
 267     ktypes = krb5_config_get_strings(context, NULL, "kadmin",
 268                                      "default_keys", NULL);
 269     if (ktypes == NULL)
 270         ktypes = default_keytypes;
 271
 272     *ret_key_set = key_set = NULL;
 273     *nkeyset = 0;
 274
 275     ret = 0;
 276
 277     for(kp = ktypes; kp && *kp; kp++) {
 278         const char *p;
 279         krb5_salt salt;
 280         krb5_enctype *enctypes;
 281         size_t num_enctypes;
 282
 283         p = *kp;
 284         /* check alias */
 285         if(strcmp(p, "v5") == 0)
 286             p = "pw-salt";
 287         else if(strcmp(p, "v4") == 0)
 288             p = "des:pw-salt:";
 289         else if(strcmp(p, "afs") == 0 || strcmp(p, "afs3") == 0)
 290             p = "des:afs3-salt";
 291         else if (strcmp(p, "arcfour-hmac-md5") == 0)
 292             p = "arcfour-hmac-md5:pw-salt";
 293
 294         memset(&salt, 0, sizeof(salt));
 295
 296         ret = parse_key_set(context, p,
 297                             &enctypes, &num_enctypes, &salt, principal);
 298         if (ret) {
 299             krb5_warn(context, ret, "bad value for default_keys `%s'", *kp);
 300             ret = 0;
 301             continue;
 302         }
 303
 304         for (i = 0; i < num_enctypes; i++) {
 305             /* find duplicates */
 306             for (j = 0; j < *nkeyset; j++) {
 307
 308                 k = &key_set[j];
 309
 310                 if (k->key.keytype == enctypes[i]) {
 311                     if (no_salt)
 312                         break;
 313                     if (k->salt == NULL && salt.salttype == KRB5_PW_SALT)
 314                         break;
 315                     if (k->salt->type == salt.salttype &&
 316                         k->salt->salt.length == salt.saltvalue.length &&
 317                         memcmp(k->salt->salt.data, salt.saltvalue.data,
 318                                salt.saltvalue.length) == 0)
 319                         break;
 320                 }
 321             }
 322             /* not a duplicate, lets add it */
 323             if (j == *nkeyset) {
 324                 ret = add_enctype_to_key_set(&key_set, nkeyset, enctypes[i],
 325                                              no_salt ? NULL : &salt);
 326                 if (ret) {
 327                     free(enctypes);
 328                     krb5_free_salt(context, salt);
 329                     goto out;
 330                 }
 331             }
 332         }
 333         free(enctypes);
 334         krb5_free_salt(context, salt);
 335     }
 336
 337     *ret_key_set = key_set;
 338
 339  out:
 340     if (ktypes != default_keytypes)
 341         krb5_config_free_strings(ktypes);
 342
 343     if (ret) {
 344         krb5_warn(context, ret,
 345                   "failed to parse the [kadmin]default_keys values");
 346
 347         for (i = 0; i < *nkeyset; i++)
 348             free_Key(&key_set[i]);
 349         free(key_set);
 350     } else if (*nkeyset == 0) {
 351         krb5_warnx(context,
 352                    "failed to parse any of the [kadmin]default_keys values");
 353         ret = EINVAL; /* XXX */
 354     }
 355
 356     return ret;
 357 }
 358
 359
 360 krb5_error_code
 361 hdb_generate_key_set_password(krb5_context context,
 362                               krb5_principal principal,
 363                               const char *password,
 364                               Key **keys, size_t *num_keys)
 365 {
 366     krb5_error_code ret;
 367     int i;
 368
 369     ret = hdb_generate_key_set(context, principal,
 370                                 keys, num_keys, 0);
 371     if (ret)
 372         return ret;
 373
 374     for (i = 0; i < (*num_keys); i++) {
 375         krb5_salt salt;
 376
 377         salt.salttype = (*keys)[i].salt->type;
 378         salt.saltvalue.length = (*keys)[i].salt->salt.length;
 379         salt.saltvalue.data = (*keys)[i].salt->salt.data;
 380
 381         ret = krb5_string_to_key_salt (context,
 382                                        (*keys)[i].key.keytype,
 383                                        password,
 384                                        salt,
 385                                        &(*keys)[i].key);
 386
 387         if(ret)
 388             break;
 389     }
 390
 391     if(ret) {
 392         hdb_free_keys (context, *num_keys, *keys);
 393         return ret;
 394     }
 395     return ret;
 396 }