lib/hdb/keytab.c

   1 /*
   2  * Copyright (c) 1999 - 2002 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 /* keytab backend for HDB databases */
  37
  38 struct hdb_data {
  39     char *dbname;
  40     char *mkey;
  41 };
  42
  43 struct hdb_cursor {
  44     HDB *db;
  45     hdb_entry hdb_entry;
  46     int first, next;
  47     int key_idx;
  48 };
  49
  50 /*
  51  * the format for HDB keytabs is:
  52  * HDB:[HDBFORMAT:database-specific-data[:mkey=mkey-file]]
  53  */
  54
  55 static krb5_error_code KRB5_CALLCONV
  56 hdb_resolve(krb5_context context, const char *name, krb5_keytab id)
  57 {
  58     struct hdb_data *d;
  59     const char *db, *mkey;
  60
  61     d = malloc(sizeof(*d));
  62     if(d == NULL) {
  63         krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
  64         return ENOMEM;
  65     }
  66     db = name;
  67     mkey = strstr(name, ":mkey=");
  68     if(mkey == NULL || mkey[6] == '\0') {
  69         if(*name == '\0')
  70             d->dbname = NULL;
  71         else {
  72             d->dbname = strdup(name);
  73             if(d->dbname == NULL) {
  74                 free(d);
  75                 krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
  76                 return ENOMEM;
  77             }
  78         }
  79         d->mkey = NULL;
  80     } else {
  81         d->dbname = malloc(mkey - db + 1);
  82         if(d->dbname == NULL) {
  83             free(d);
  84             krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
  85             return ENOMEM;
  86         }
  87         memmove(d->dbname, db, mkey - db);
  88         d->dbname[mkey - db] = '\0';
  89
  90         d->mkey = strdup(mkey + 6);
  91         if(d->mkey == NULL) {
  92             free(d->dbname);
  93             free(d);
  94             krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
  95             return ENOMEM;
  96         }
  97     }
  98     id->data = d;
  99     return 0;
 100 }
 101
 102 static krb5_error_code KRB5_CALLCONV
 103 hdb_close(krb5_context context, krb5_keytab id)
 104 {
 105     struct hdb_data *d = id->data;
 106
 107     free(d->dbname);
 108     free(d->mkey);
 109     free(d);
 110     return 0;
 111 }
 112
 113 static krb5_error_code KRB5_CALLCONV
 114 hdb_get_name(krb5_context context,
 115              krb5_keytab id,
 116              char *name,
 117              size_t namesize)
 118 {
 119     struct hdb_data *d = id->data;
 120
 121     snprintf(name, namesize, "%s%s%s",
 122              d->dbname ? d->dbname : "",
 123              (d->dbname || d->mkey) ? ":" : "",
 124              d->mkey ? d->mkey : "");
 125     return 0;
 126 }
 127
 128 /*
 129  * try to figure out the database (`dbname') and master-key (`mkey')
 130  * that should be used for `principal'.
 131  */
 132
 133 static krb5_error_code
 134 find_db (krb5_context context,
 135          char **dbname,
 136          char **mkey,
 137          krb5_const_principal principal)
 138 {
 139     krb5_const_realm realm = krb5_principal_get_realm(context, principal);
 140     krb5_error_code ret;
 141     struct hdb_dbinfo *head, *dbinfo = NULL;
 142
 143     *dbname = *mkey = NULL;
 144
 145     ret = hdb_get_dbinfo(context, &head);
 146     if (ret)
 147         return ret;
 148
 149     while ((dbinfo = hdb_dbinfo_get_next(head, dbinfo)) != NULL) {
 150         const char *p = hdb_dbinfo_get_realm(context, dbinfo);
 151         if (p && strcmp (realm, p) == 0) {
 152             p = hdb_dbinfo_get_dbname(context, dbinfo);
 153             if (p)
 154                 *dbname = strdup(p);
 155             p = hdb_dbinfo_get_mkey_file(context, dbinfo);
 156             if (p)
 157                 *mkey = strdup(p);
 158             break;
 159         }
 160     }
 161     hdb_free_dbinfo(context, &head);
 162     if (*dbname == NULL &&
 163         (*dbname = strdup(hdb_default_db(context))) == NULL) {
 164         free(*mkey);
 165         *mkey = NULL;
 166         return krb5_enomem(context);
 167     }
 168     return 0;
 169 }
 170
 171 /*
 172  * find the keytab entry in `id' for `principal, kvno, enctype' and return
 173  * it in `entry'.  return 0 or an error code
 174  */
 175
 176 static krb5_error_code KRB5_CALLCONV
 177 hdb_get_entry(krb5_context context,
 178               krb5_keytab id,
 179               krb5_const_principal principal,
 180               krb5_kvno kvno,
 181               krb5_enctype enctype,
 182               krb5_keytab_entry *entry)
 183 {
 184     hdb_entry ent;
 185     krb5_error_code ret;
 186     struct hdb_data *d = id->data;
 187     const char *dbname = d->dbname;
 188     const char *mkey   = d->mkey;
 189     char *fdbname = NULL, *fmkey = NULL;
 190     HDB *db;
 191     size_t i;
 192
 193     if (!principal)
 194         return KRB5_KT_NOTFOUND;
 195
 196     memset(&ent, 0, sizeof(ent));
 197
 198     if (dbname == NULL) {
 199         ret = find_db(context, &fdbname, &fmkey, principal);
 200         if (ret)
 201             return ret;
 202         dbname = fdbname;
 203         mkey = fmkey;
 204     }
 205
 206     ret = hdb_create (context, &db, dbname);
 207     if (ret)
 208         goto out2;
 209     ret = hdb_set_master_keyfile (context, db, mkey);
 210     if (ret) {
 211         (*db->hdb_destroy)(context, db);
 212         goto out2;
 213     }
 214
 215     ret = (*db->hdb_open)(context, db, O_RDONLY, 0);
 216     if (ret) {
 217         (*db->hdb_destroy)(context, db);
 218         goto out2;
 219     }
 220
 221     ret = hdb_fetch_kvno(context, db, principal,
 222                          HDB_F_DECRYPT|HDB_F_KVNO_SPECIFIED|
 223                          HDB_F_GET_CLIENT|HDB_F_GET_SERVER|HDB_F_GET_KRBTGT,
 224                          0, 0, kvno, &ent);
 225
 226     if (ret == HDB_ERR_WRONG_REALM || ret == HDB_ERR_NOENTRY)
 227         ret = KRB5_KT_NOTFOUND;
 228     if (ret)
 229         goto out;
 230
 231     if(kvno && (krb5_kvno)ent.kvno != kvno) {
 232         hdb_free_entry(context, db, &ent);
 233         ret = KRB5_KT_NOTFOUND;
 234         goto out;
 235     }
 236     if(enctype == 0)
 237         if(ent.keys.len > 0)
 238             enctype = ent.keys.val[0].key.keytype;
 239     ret = KRB5_KT_NOTFOUND;
 240     for(i = 0; i < ent.keys.len; i++) {
 241         if(ent.keys.val[i].key.keytype == enctype) {
 242             krb5_copy_principal(context, principal, &entry->principal);
 243             entry->vno = ent.kvno;
 244             krb5_copy_keyblock_contents(context,
 245                                         &ent.keys.val[i].key,
 246                                         &entry->keyblock);
 247             ret = 0;
 248             break;
 249         }
 250     }
 251     hdb_free_entry(context, db, &ent);
 252  out:
 253     (*db->hdb_close)(context, db);
 254     (*db->hdb_destroy)(context, db);
 255  out2:
 256     free(fdbname);
 257     free(fmkey);
 258     return ret;
 259 }
 260
 261 /*
 262  * find the keytab entry in `id' for `principal, kvno, enctype' and return
 263  * it in `entry'.  return 0 or an error code
 264  */
 265
 266 static krb5_error_code KRB5_CALLCONV
 267 hdb_start_seq_get(krb5_context context,
 268                   krb5_keytab id,
 269                   krb5_kt_cursor *cursor)
 270 {
 271     krb5_error_code ret;
 272     struct hdb_cursor *c;
 273     struct hdb_data *d = id->data;
 274     const char *dbname = d->dbname;
 275     const char *mkey   = d->mkey;
 276     HDB *db;
 277
 278     if (dbname == NULL) {
 279         /*
 280          * We don't support enumerating without being told what
 281          * backend to enumerate on
 282          */
 283         ret = KRB5_KT_NOTFOUND;
 284         return ret;
 285     }
 286
 287     ret = hdb_create (context, &db, dbname);
 288     if (ret)
 289         return ret;
 290     ret = hdb_set_master_keyfile (context, db, mkey);
 291     if (ret) {
 292         (*db->hdb_destroy)(context, db);
 293         return ret;
 294     }
 295
 296     ret = (*db->hdb_open)(context, db, O_RDONLY, 0);
 297     if (ret) {
 298         (*db->hdb_destroy)(context, db);
 299         return ret;
 300     }
 301
 302     cursor->data = c = malloc (sizeof(*c));
 303     if(c == NULL){
 304         (*db->hdb_close)(context, db);
 305         (*db->hdb_destroy)(context, db);
 306         krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
 307         return ENOMEM;
 308     }
 309
 310     c->db = db;
 311     c->first = TRUE;
 312     c->next = TRUE;
 313     c->key_idx = 0;
 314
 315     cursor->data = c;
 316     return ret;
 317 }
 318
 319 static int KRB5_CALLCONV
 320 hdb_next_entry(krb5_context context,
 321                krb5_keytab id,
 322                krb5_keytab_entry *entry,
 323                krb5_kt_cursor *cursor)
 324 {
 325     struct hdb_cursor *c = cursor->data;
 326     krb5_error_code ret;
 327
 328     memset(entry, 0, sizeof(*entry));
 329
 330     if (c->first) {
 331         c->first = FALSE;
 332         ret = (c->db->hdb_firstkey)(context, c->db,
 333                                     HDB_F_DECRYPT|
 334                                     HDB_F_GET_CLIENT|HDB_F_GET_SERVER|HDB_F_GET_KRBTGT,
 335                                     &c->hdb_entry);
 336         if (ret == HDB_ERR_NOENTRY)
 337             return KRB5_KT_END;
 338         else if (ret)
 339             return ret;
 340
 341         if (c->hdb_entry.keys.len == 0)
 342             hdb_free_entry(context, c->db, &c->hdb_entry);
 343         else
 344             c->next = FALSE;
 345     }
 346
 347     while (c->next) {
 348         ret = (c->db->hdb_nextkey)(context, c->db,
 349                                    HDB_F_DECRYPT|
 350                                    HDB_F_GET_CLIENT|HDB_F_GET_SERVER|HDB_F_GET_KRBTGT,
 351                                    &c->hdb_entry);
 352         if (ret == HDB_ERR_NOENTRY)
 353             return KRB5_KT_END;
 354         else if (ret)
 355             return ret;
 356
 357         /* If no keys on this entry, try again */
 358         if (c->hdb_entry.keys.len == 0)
 359             hdb_free_entry(context, c->db, &c->hdb_entry);
 360         else
 361             c->next = FALSE;
 362     }
 363
 364     /*
 365      * Return next enc type (keytabs are one slot per key, while
 366      * hdb is one record per principal.
 367      */
 368
 369     ret = krb5_copy_principal(context,
 370                               c->hdb_entry.principal,
 371                               &entry->principal);
 372     if (ret)
 373         return ret;
 374
 375     entry->vno = c->hdb_entry.kvno;
 376     ret = krb5_copy_keyblock_contents(context,
 377                                       &c->hdb_entry.keys.val[c->key_idx].key,
 378                                       &entry->keyblock);
 379     if (ret) {
 380         krb5_free_principal(context, entry->principal);
 381         memset(entry, 0, sizeof(*entry));
 382         return ret;
 383     }
 384     c->key_idx++;
 385
 386     /*
 387      * Once we get to the end of the list, signal that we want the
 388      * next entry
 389      */
 390
 391     if ((size_t)c->key_idx == c->hdb_entry.keys.len) {
 392         hdb_free_entry(context, c->db, &c->hdb_entry);
 393         c->next = TRUE;
 394         c->key_idx = 0;
 395     }
 396
 397     return 0;
 398 }
 399
 400
 401 static int KRB5_CALLCONV
 402 hdb_end_seq_get(krb5_context context,
 403                 krb5_keytab id,
 404                 krb5_kt_cursor *cursor)
 405 {
 406     struct hdb_cursor *c = cursor->data;
 407
 408     if (!c->next)
 409         hdb_free_entry(context, c->db, &c->hdb_entry);
 410
 411     (c->db->hdb_close)(context, c->db);
 412     (c->db->hdb_destroy)(context, c->db);
 413
 414     free(c);
 415     return 0;
 416 }
 417
 418 krb5_kt_ops hdb_kt_ops = {
 419     "HDB",
 420     hdb_resolve,
 421     hdb_get_name,
 422     hdb_close,
 423     NULL,               /* destroy */
 424     hdb_get_entry,
 425     hdb_start_seq_get,
 426     hdb_next_entry,
 427     hdb_end_seq_get,
 428     NULL,               /* add */
 429     NULL,               /* remove */
 430     NULL,
 431     0
 432 };
 433
 434 krb5_kt_ops hdb_get_kt_ops = {
 435     "HDBGET",
 436     hdb_resolve,
 437     hdb_get_name,
 438     hdb_close,
 439     NULL,
 440     hdb_get_entry,
 441     NULL,
 442     NULL,
 443     NULL,
 444     NULL,
 445     NULL,
 446     NULL,
 447     0
 448 };