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:[database:file:mkey]
  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 = strchr(name, ':');
  68     if(mkey == NULL || mkey[1] == '\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         if((mkey - db) == 0) {
  82             d->dbname = NULL;
  83         } else {
  84             d->dbname = malloc(mkey - db + 1);
  85             if(d->dbname == NULL) {
  86                 free(d);
  87                 krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
  88                 return ENOMEM;
  89             }
  90             memmove(d->dbname, db, mkey - db);
  91             d->dbname[mkey - db] = '\0';
  92         }
  93         d->mkey = strdup(mkey + 1);
  94         if(d->mkey == NULL) {
  95             free(d->dbname);
  96             free(d);
  97             krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
  98             return ENOMEM;
  99         }
 100     }
 101     id->data = d;
 102     return 0;
 103 }
 104
 105 static krb5_error_code
 106 hdb_close(krb5_context context, krb5_keytab id)
 107 {
 108     struct hdb_data *d = id->data;
 109
 110     free(d->dbname);
 111     free(d->mkey);
 112     free(d);
 113     return 0;
 114 }
 115
 116 static krb5_error_code
 117 hdb_get_name(krb5_context context,
 118              krb5_keytab id,
 119              char *name,
 120              size_t namesize)
 121 {
 122     struct hdb_data *d = id->data;
 123
 124     snprintf(name, namesize, "%s%s%s",
 125              d->dbname ? d->dbname : "",
 126              (d->dbname || d->mkey) ? ":" : "",
 127              d->mkey ? d->mkey : "");
 128     return 0;
 129 }
 130
 131 /*
 132  * try to figure out the database (`dbname') and master-key (`mkey')
 133  * that should be used for `principal'.
 134  */
 135
 136 static krb5_error_code
 137 find_db (krb5_context context,
 138          char **dbname,
 139          char **mkey,
 140          krb5_const_principal principal)
 141 {
 142     krb5_const_realm realm = krb5_principal_get_realm(context, principal);
 143     krb5_error_code ret;
 144     struct hdb_dbinfo *head, *dbinfo = NULL;
 145
 146     *dbname = *mkey = NULL;
 147
 148     ret = hdb_get_dbinfo(context, &head);
 149     if (ret)
 150         return ret;
 151
 152     while ((dbinfo = hdb_dbinfo_get_next(head, dbinfo)) != NULL) {
 153         const char *p = hdb_dbinfo_get_realm(context, dbinfo);
 154         if (p && strcmp (realm, p) == 0) {
 155             p = hdb_dbinfo_get_dbname(context, dbinfo);
 156             if (p)
 157                 *dbname = strdup(p);
 158             p = hdb_dbinfo_get_mkey_file(context, dbinfo);
 159             if (p)
 160                 *mkey = strdup(p);
 161             break;
 162         }
 163     }
 164     hdb_free_dbinfo(context, &head);
 165     if (*dbname == NULL)
 166         *dbname = strdup(HDB_DEFAULT_DB);
 167     return 0;
 168 }
 169
 170 /*
 171  * find the keytab entry in `id' for `principal, kvno, enctype' and return
 172  * it in `entry'.  return 0 or an error code
 173  */
 174
 175 static krb5_error_code
 176 hdb_get_entry(krb5_context context,
 177               krb5_keytab id,
 178               krb5_const_principal principal,
 179               krb5_kvno kvno,
 180               krb5_enctype enctype,
 181               krb5_keytab_entry *entry)
 182 {
 183     hdb_entry_ex ent;
 184     krb5_error_code ret;
 185     struct hdb_data *d = id->data;
 186     const char *dbname = d->dbname;
 187     const char *mkey   = d->mkey;
 188     char *fdbname = NULL, *fmkey = NULL;
 189     HDB *db;
 190     int i;
 191
 192     memset(&ent, 0, sizeof(ent));
 193
 194     if (dbname == NULL) {
 195         ret = find_db(context, &fdbname, &fmkey, principal);
 196         if (ret)
 197             return ret;
 198         dbname = fdbname;
 199         mkey = fmkey;
 200     }
 201
 202     ret = hdb_create (context, &db, dbname);
 203     if (ret)
 204         goto out2;
 205     ret = hdb_set_master_keyfile (context, db, mkey);
 206     if (ret) {
 207         (*db->hdb_destroy)(context, db);
 208         goto out2;
 209     }
 210
 211     ret = (*db->hdb_open)(context, db, O_RDONLY, 0);
 212     if (ret) {
 213         (*db->hdb_destroy)(context, db);
 214         goto out2;
 215     }
 216     ret = (*db->hdb_fetch)(context, db, principal,
 217                            HDB_F_DECRYPT|
 218                            HDB_F_GET_CLIENT|HDB_F_GET_SERVER|HDB_F_GET_KRBTGT,
 219                            &ent);
 220
 221     if(ret == HDB_ERR_NOENTRY) {
 222         ret = KRB5_KT_NOTFOUND;
 223         goto out;
 224     }else if(ret)
 225         goto out;
 226
 227     if(kvno && ent.entry.kvno != kvno) {
 228         hdb_free_entry(context, &ent);
 229         ret = KRB5_KT_NOTFOUND;
 230         goto out;
 231     }
 232     if(enctype == 0)
 233         if(ent.entry.keys.len > 0)
 234             enctype = ent.entry.keys.val[0].key.keytype;
 235     ret = KRB5_KT_NOTFOUND;
 236     for(i = 0; i < ent.entry.keys.len; i++) {
 237         if(ent.entry.keys.val[i].key.keytype == enctype) {
 238             krb5_copy_principal(context, principal, &entry->principal);
 239             entry->vno = ent.entry.kvno;
 240             krb5_copy_keyblock_contents(context,
 241                                         &ent.entry.keys.val[i].key,
 242                                         &entry->keyblock);
 243             ret = 0;
 244             break;
 245         }
 246     }
 247     hdb_free_entry(context, &ent);
 248  out:
 249     (*db->hdb_close)(context, db);
 250     (*db->hdb_destroy)(context, db);
 251  out2:
 252     free(fdbname);
 253     free(fmkey);
 254     return ret;
 255 }
 256
 257 /*
 258  * find the keytab entry in `id' for `principal, kvno, enctype' and return
 259  * it in `entry'.  return 0 or an error code
 260  */
 261
 262 static krb5_error_code
 263 hdb_start_seq_get(krb5_context context,
 264                   krb5_keytab id,
 265                   krb5_kt_cursor *cursor)
 266 {
 267     krb5_error_code ret;
 268     struct hdb_cursor *c;
 269     struct hdb_data *d = id->data;
 270     const char *dbname = d->dbname;
 271     const char *mkey   = d->mkey;
 272     HDB *db;
 273
 274     if (dbname == NULL) {
 275         /*
 276          * We don't support enumerating without being told what
 277          * backend to enumerate on
 278          */
 279         ret = KRB5_KT_NOTFOUND;
 280         return ret;
 281     }
 282
 283     ret = hdb_create (context, &db, dbname);
 284     if (ret)
 285         return ret;
 286     ret = hdb_set_master_keyfile (context, db, mkey);
 287     if (ret) {
 288         (*db->hdb_destroy)(context, db);
 289         return ret;
 290     }
 291
 292     ret = (*db->hdb_open)(context, db, O_RDONLY, 0);
 293     if (ret) {
 294         (*db->hdb_destroy)(context, db);
 295         return ret;
 296     }
 297
 298     cursor->data = c = malloc (sizeof(*c));
 299     if(c == NULL){
 300         (*db->hdb_close)(context, db);
 301         (*db->hdb_destroy)(context, db);
 302         krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
 303         return ENOMEM;
 304     }
 305
 306     c->db = db;
 307     c->first = TRUE;
 308     c->next = TRUE;
 309     c->key_idx = 0;
 310
 311     cursor->data = c;
 312     return ret;
 313 }
 314
 315 static int
 316 hdb_next_entry(krb5_context context,
 317                krb5_keytab id,
 318                krb5_keytab_entry *entry,
 319                krb5_kt_cursor *cursor)
 320 {
 321     struct hdb_cursor *c = cursor->data;
 322     krb5_error_code ret;
 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         krb5_copy_principal(context,
 364                             c->hdb_entry.entry.principal,
 365                             &entry->principal);
 366         entry->vno = c->hdb_entry.entry.kvno;
 367         krb5_copy_keyblock_contents(context,
 368                                     &c->hdb_entry.entry.keys.val[c->key_idx].key,
 369                                     &entry->keyblock);
 370         c->key_idx++;
 371
 372         /*
 373          * Once we get to the end of the list, signal that we want the
 374          * next entry
 375          */
 376
 377         if (c->key_idx == c->hdb_entry.entry.keys.len) {
 378                 hdb_free_entry(context, &c->hdb_entry);
 379                 c->next = TRUE;
 380                 c->key_idx = 0;
 381         }
 382         return 0;
 383 }
 384
 385
 386 static int hdb_end_seq_get(krb5_context context,
 387                            krb5_keytab id,
 388                            krb5_kt_cursor *cursor) {
 389     struct hdb_cursor *c = cursor->data;
 390     (c->db->hdb_close)(context, c->db);
 391     (c->db->hdb_destroy)(context, c->db);
 392     if (!c->next) {
 393         hdb_free_entry(context, &c->hdb_entry);
 394     }
 395     free(c);
 396     return 0;
 397 }
 398
 399 krb5_kt_ops hdb_kt_ops = {
 400     "HDB",
 401     hdb_resolve,
 402     hdb_get_name,
 403     hdb_close,
 404     NULL,               /* destroy */
 405     hdb_get_entry,
 406     hdb_start_seq_get,
 407     hdb_next_entry,
 408     hdb_end_seq_get,
 409     NULL,               /* add */
 410     NULL                /* remove */
 411 };