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 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[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 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);
 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 KRB5_CALLCONV
 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     size_t 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
 214     ret = (*db->hdb_fetch_kvno)(context, db, principal,
 215                                 HDB_F_DECRYPT|HDB_F_KVNO_SPECIFIED|
 216                                 HDB_F_GET_CLIENT|HDB_F_GET_SERVER|HDB_F_GET_KRBTGT,
 217                                 kvno, &ent);
 218
 219     if(ret == HDB_ERR_NOENTRY) {
 220         ret = KRB5_KT_NOTFOUND;
 221         goto out;
 222     }else if(ret)
 223         goto out;
 224
 225     if(kvno && (krb5_kvno)ent.entry.kvno != kvno) {
 226         hdb_free_entry(context, &ent);
 227         ret = KRB5_KT_NOTFOUND;
 228         goto out;
 229     }
 230     if(enctype == 0)
 231         if(ent.entry.keys.len > 0)
 232             enctype = ent.entry.keys.val[0].key.keytype;
 233     ret = KRB5_KT_NOTFOUND;
 234     for(i = 0; i < ent.entry.keys.len; i++) {
 235         if(ent.entry.keys.val[i].key.keytype == enctype) {
 236             krb5_copy_principal(context, principal, &entry->principal);
 237             entry->vno = ent.entry.kvno;
 238             krb5_copy_keyblock_contents(context,
 239                                         &ent.entry.keys.val[i].key,
 240                                         &entry->keyblock);
 241             ret = 0;
 242             break;
 243         }
 244     }
 245     hdb_free_entry(context, &ent);
 246  out:
 247     (*db->hdb_close)(context, db);
 248     (*db->hdb_destroy)(context, db);
 249  out2:
 250     free(fdbname);
 251     free(fmkey);
 252     return ret;
 253 }
 254
 255 /*
 256  * find the keytab entry in `id' for `principal, kvno, enctype' and return
 257  * it in `entry'.  return 0 or an error code
 258  */
 259
 260 static krb5_error_code KRB5_CALLCONV
 261 hdb_start_seq_get(krb5_context context,
 262                   krb5_keytab id,
 263                   krb5_kt_cursor *cursor)
 264 {
 265     krb5_error_code ret;
 266     struct hdb_cursor *c;
 267     struct hdb_data *d = id->data;
 268     const char *dbname = d->dbname;
 269     const char *mkey   = d->mkey;
 270     HDB *db;
 271
 272     if (dbname == NULL) {
 273         /*
 274          * We don't support enumerating without being told what
 275          * backend to enumerate on
 276          */
 277         ret = KRB5_KT_NOTFOUND;
 278         return ret;
 279     }
 280
 281     ret = hdb_create (context, &db, dbname);
 282     if (ret)
 283         return ret;
 284     ret = hdb_set_master_keyfile (context, db, mkey);
 285     if (ret) {
 286         (*db->hdb_destroy)(context, db);
 287         return ret;
 288     }
 289
 290     ret = (*db->hdb_open)(context, db, O_RDONLY, 0);
 291     if (ret) {
 292         (*db->hdb_destroy)(context, db);
 293         return ret;
 294     }
 295
 296     cursor->data = c = malloc (sizeof(*c));
 297     if(c == NULL){
 298         (*db->hdb_close)(context, db);
 299         (*db->hdb_destroy)(context, db);
 300         krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
 301         return ENOMEM;
 302     }
 303
 304     c->db = db;
 305     c->first = TRUE;
 306     c->next = TRUE;
 307     c->key_idx = 0;
 308
 309     cursor->data = c;
 310     return ret;
 311 }
 312
 313 static int KRB5_CALLCONV
 314 hdb_next_entry(krb5_context context,
 315                krb5_keytab id,
 316                krb5_keytab_entry *entry,
 317                krb5_kt_cursor *cursor)
 318 {
 319     struct hdb_cursor *c = cursor->data;
 320     krb5_error_code ret;
 321
 322     memset(entry, 0, sizeof(*entry));
 323
 324     if (c->first) {
 325         c->first = FALSE;
 326         ret = (c->db->hdb_firstkey)(context, c->db,
 327                                     HDB_F_DECRYPT|
 328                                     HDB_F_GET_CLIENT|HDB_F_GET_SERVER|HDB_F_GET_KRBTGT,
 329                                     &c->hdb_entry);
 330         if (ret == HDB_ERR_NOENTRY)
 331             return KRB5_KT_END;
 332         else if (ret)
 333             return ret;
 334
 335         if (c->hdb_entry.entry.keys.len == 0)
 336             hdb_free_entry(context, &c->hdb_entry);
 337         else
 338             c->next = FALSE;
 339     }
 340
 341     while (c->next) {
 342         ret = (c->db->hdb_nextkey)(context, c->db,
 343                                    HDB_F_DECRYPT|
 344                                    HDB_F_GET_CLIENT|HDB_F_GET_SERVER|HDB_F_GET_KRBTGT,
 345                                    &c->hdb_entry);
 346         if (ret == HDB_ERR_NOENTRY)
 347             return KRB5_KT_END;
 348         else if (ret)
 349             return ret;
 350
 351         /* If no keys on this entry, try again */
 352         if (c->hdb_entry.entry.keys.len == 0)
 353             hdb_free_entry(context, &c->hdb_entry);
 354         else
 355             c->next = FALSE;
 356     }
 357
 358     /*
 359      * Return next enc type (keytabs are one slot per key, while
 360      * hdb is one record per principal.
 361      */
 362
 363     ret = krb5_copy_principal(context,
 364                               c->hdb_entry.entry.principal,
 365                               &entry->principal);
 366     if (ret)
 367         return ret;
 368
 369     entry->vno = c->hdb_entry.entry.kvno;
 370     ret = krb5_copy_keyblock_contents(context,
 371                                       &c->hdb_entry.entry.keys.val[c->key_idx].key,
 372                                       &entry->keyblock);
 373     if (ret) {
 374         krb5_free_principal(context, entry->principal);
 375         memset(entry, 0, sizeof(*entry));
 376         return ret;
 377     }
 378     c->key_idx++;
 379
 380     /*
 381      * Once we get to the end of the list, signal that we want the
 382      * next entry
 383      */
 384
 385     if ((size_t)c->key_idx == c->hdb_entry.entry.keys.len) {
 386         hdb_free_entry(context, &c->hdb_entry);
 387         c->next = TRUE;
 388         c->key_idx = 0;
 389     }
 390
 391     return 0;
 392 }
 393
 394
 395 static int KRB5_CALLCONV
 396 hdb_end_seq_get(krb5_context context,
 397                 krb5_keytab id,
 398                 krb5_kt_cursor *cursor)
 399 {
 400     struct hdb_cursor *c = cursor->data;
 401
 402     if (!c->next)
 403         hdb_free_entry(context, &c->hdb_entry);
 404
 405     (c->db->hdb_close)(context, c->db);
 406     (c->db->hdb_destroy)(context, c->db);
 407
 408     free(c);
 409     return 0;
 410 }
 411
 412 krb5_kt_ops hdb_kt_ops = {
 413     "HDB",
 414     hdb_resolve,
 415     hdb_get_name,
 416     hdb_close,
 417     NULL,               /* destroy */
 418     hdb_get_entry,
 419     hdb_start_seq_get,
 420     hdb_next_entry,
 421     hdb_end_seq_get,
 422     NULL,               /* add */
 423     NULL                /* remove */
 424 };