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_ex 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
  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[5] == '\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 + 5);
  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
 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
 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);
 164     return 0;
 165 }
 166
 167 /*
 168  * find the keytab entry in `id' for `principal, kvno, enctype' and return
 169  * it in `entry'.  return 0 or an error code
 170  */
 171
 172 static krb5_error_code
 173 hdb_get_entry(krb5_context context,
 174               krb5_keytab id,
 175               krb5_const_principal principal,
 176               krb5_kvno kvno,
 177               krb5_enctype enctype,
 178               krb5_keytab_entry *entry)
 179 {
 180     hdb_entry_ex ent;
 181     krb5_error_code ret;
 182     struct hdb_data *d = id->data;
 183     const char *dbname = d->dbname;
 184     const char *mkey   = d->mkey;
 185     char *fdbname = NULL, *fmkey = NULL;
 186     HDB *db;
 187     int i;
 188
 189     memset(&ent, 0, sizeof(ent));
 190
 191     if (dbname == NULL) {
 192         ret = find_db(context, &fdbname, &fmkey, principal);
 193         if (ret)
 194             return ret;
 195         dbname = fdbname;
 196         mkey = fmkey;
 197     }
 198
 199     ret = hdb_create (context, &db, dbname);
 200     if (ret)
 201         goto out2;
 202     ret = hdb_set_master_keyfile (context, db, mkey);
 203     if (ret) {
 204         (*db->hdb_destroy)(context, db);
 205         goto out2;
 206     }
 207
 208     ret = (*db->hdb_open)(context, db, O_RDONLY, 0);
 209     if (ret) {
 210         (*db->hdb_destroy)(context, db);
 211         goto out2;
 212     }
 213     ret = (*db->hdb_fetch)(context, db, principal,
 214                            HDB_F_DECRYPT|
 215                            HDB_F_GET_CLIENT|HDB_F_GET_SERVER|HDB_F_GET_KRBTGT,
 216                            &ent);
 217
 218     if(ret == HDB_ERR_NOENTRY) {
 219         ret = KRB5_KT_NOTFOUND;
 220         goto out;
 221     }else if(ret)
 222         goto out;
 223
 224     if(kvno && ent.entry.kvno != kvno) {
 225         hdb_free_entry(context, &ent);
 226         ret = KRB5_KT_NOTFOUND;
 227         goto out;
 228     }
 229     if(enctype == 0)
 230         if(ent.entry.keys.len > 0)
 231             enctype = ent.entry.keys.val[0].key.keytype;
 232     ret = KRB5_KT_NOTFOUND;
 233     for(i = 0; i < ent.entry.keys.len; i++) {
 234         if(ent.entry.keys.val[i].key.keytype == enctype) {
 235             krb5_copy_principal(context, principal, &entry->principal);
 236             entry->vno = ent.entry.kvno;
 237             krb5_copy_keyblock_contents(context,
 238                                         &ent.entry.keys.val[i].key,
 239                                         &entry->keyblock);
 240             ret = 0;
 241             break;
 242         }
 243     }
 244     hdb_free_entry(context, &ent);
 245  out:
 246     (*db->hdb_close)(context, db);
 247     (*db->hdb_destroy)(context, db);
 248  out2:
 249     free(fdbname);
 250     free(fmkey);
 251     return ret;
 252 }
 253
 254 /*
 255  * find the keytab entry in `id' for `principal, kvno, enctype' and return
 256  * it in `entry'.  return 0 or an error code
 257  */
 258
 259 static krb5_error_code
 260 hdb_start_seq_get(krb5_context context,
 261                   krb5_keytab id,
 262                   krb5_kt_cursor *cursor)
 263 {
 264     krb5_error_code ret;
 265     struct hdb_cursor *c;
 266     struct hdb_data *d = id->data;
 267     const char *dbname = d->dbname;
 268     const char *mkey   = d->mkey;
 269     HDB *db;
 270
 271     if (dbname == NULL) {
 272         /*
 273          * We don't support enumerating without being told what
 274          * backend to enumerate on
 275          */
 276         ret = KRB5_KT_NOTFOUND;
 277         return ret;
 278     }
 279
 280     ret = hdb_create (context, &db, dbname);
 281     if (ret)
 282         return ret;
 283     ret = hdb_set_master_keyfile (context, db, mkey);
 284     if (ret) {
 285         (*db->hdb_destroy)(context, db);
 286         return ret;
 287     }
 288
 289     ret = (*db->hdb_open)(context, db, O_RDONLY, 0);
 290     if (ret) {
 291         (*db->hdb_destroy)(context, db);
 292         return ret;
 293     }
 294
 295     cursor->data = c = malloc (sizeof(*c));
 296     if(c == NULL){
 297         (*db->hdb_close)(context, db);
 298         (*db->hdb_destroy)(context, db);
 299         krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
 300         return ENOMEM;
 301     }
 302
 303     c->db = db;
 304     c->first = TRUE;
 305     c->next = TRUE;
 306     c->key_idx = 0;
 307
 308     cursor->data = c;
 309     return ret;
 310 }
 311
 312 static int
 313 hdb_next_entry(krb5_context context,
 314                krb5_keytab id,
 315                krb5_keytab_entry *entry,
 316                krb5_kt_cursor *cursor)
 317 {
 318     struct hdb_cursor *c = cursor->data;
 319     krb5_error_code ret;
 320
 321     memset(entry, 0, sizeof(*entry));
 322
 323     if (c->first) {
 324         c->first = FALSE;
 325         ret = (c->db->hdb_firstkey)(context, c->db,
 326                                     HDB_F_DECRYPT|
 327                                     HDB_F_GET_CLIENT|HDB_F_GET_SERVER|HDB_F_GET_KRBTGT,
 328                                     &c->hdb_entry);
 329         if (ret == HDB_ERR_NOENTRY)
 330             return KRB5_KT_END;
 331         else if (ret)
 332             return ret;
 333
 334         if (c->hdb_entry.entry.keys.len == 0)
 335             hdb_free_entry(context, &c->hdb_entry);
 336         else
 337             c->next = FALSE;
 338     }
 339
 340     while (c->next) {
 341         ret = (c->db->hdb_nextkey)(context, c->db,
 342                                    HDB_F_DECRYPT|
 343                                    HDB_F_GET_CLIENT|HDB_F_GET_SERVER|HDB_F_GET_KRBTGT,
 344                                    &c->hdb_entry);
 345         if (ret == HDB_ERR_NOENTRY)
 346             return KRB5_KT_END;
 347         else if (ret)
 348             return ret;
 349
 350         /* If no keys on this entry, try again */
 351         if (c->hdb_entry.entry.keys.len == 0)
 352             hdb_free_entry(context, &c->hdb_entry);
 353         else
 354             c->next = FALSE;
 355     }
 356
 357     /*
 358      * Return next enc type (keytabs are one slot per key, while
 359      * hdb is one record per principal.
 360      */
 361
 362     ret = krb5_copy_principal(context,
 363                               c->hdb_entry.entry.principal,
 364                               &entry->principal);
 365     if (ret)
 366         return ret;
 367
 368     entry->vno = c->hdb_entry.entry.kvno;
 369     ret = krb5_copy_keyblock_contents(context,
 370                                       &c->hdb_entry.entry.keys.val[c->key_idx].key,
 371                                       &entry->keyblock);
 372     if (ret) {
 373         krb5_free_principal(context, entry->principal);
 374         memset(entry, 0, sizeof(*entry));
 375         return ret;
 376     }
 377     c->key_idx++;
 378
 379     /*
 380      * Once we get to the end of the list, signal that we want the
 381      * next entry
 382      */
 383
 384     if (c->key_idx == c->hdb_entry.entry.keys.len) {
 385         hdb_free_entry(context, &c->hdb_entry);
 386         c->next = TRUE;
 387         c->key_idx = 0;
 388     }
 389
 390     return 0;
 391 }
 392
 393
 394 static int
 395 hdb_end_seq_get(krb5_context context,
 396                 krb5_keytab id,
 397                 krb5_kt_cursor *cursor)
 398 {
 399     struct hdb_cursor *c = cursor->data;
 400
 401     if (!c->next)
 402         hdb_free_entry(context, &c->hdb_entry);
 403
 404     (c->db->hdb_close)(context, c->db);
 405     (c->db->hdb_destroy)(context, c->db);
 406
 407     free(c);
 408     return 0;
 409 }
 410
 411 krb5_kt_ops hdb_kt_ops = {
 412     "HDB",
 413     hdb_resolve,
 414     hdb_get_name,
 415     hdb_close,
 416     NULL,               /* destroy */
 417     hdb_get_entry,
 418     hdb_start_seq_get,
 419     hdb_next_entry,
 420     hdb_end_seq_get,
 421     NULL,               /* add */
 422     NULL                /* remove */
 423 };