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 /*
  44  * the format for HDB keytabs is:
  45  * HDB:[database:file:mkey]
  46  */
  47
  48 static krb5_error_code
  49 hdb_resolve(krb5_context context, const char *name, krb5_keytab id)
  50 {
  51     struct hdb_data *d;
  52     const char *db, *mkey;
  53
  54     d = malloc(sizeof(*d));
  55     if(d == NULL) {
  56         krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
  57         return ENOMEM;
  58     }
  59     db = name;
  60     mkey = strchr(name, ':');
  61     if(mkey == NULL || mkey[1] == '\0') {
  62         if(*name == '\0')
  63             d->dbname = NULL;
  64         else {
  65             d->dbname = strdup(name);
  66             if(d->dbname == NULL) {
  67                 free(d);
  68                 krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
  69                 return ENOMEM;
  70             }
  71         }
  72         d->mkey = NULL;
  73     } else {
  74         if((mkey - db) == 0) {
  75             d->dbname = NULL;
  76         } else {
  77             d->dbname = malloc(mkey - db + 1);
  78             if(d->dbname == NULL) {
  79                 free(d);
  80                 krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
  81                 return ENOMEM;
  82             }
  83             memmove(d->dbname, db, mkey - db);
  84             d->dbname[mkey - db] = '\0';
  85         }
  86         d->mkey = strdup(mkey + 1);
  87         if(d->mkey == NULL) {
  88             free(d->dbname);
  89             free(d);
  90             krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
  91             return ENOMEM;
  92         }
  93     }
  94     id->data = d;
  95     return 0;
  96 }
  97
  98 static krb5_error_code
  99 hdb_close(krb5_context context, krb5_keytab id)
 100 {
 101     struct hdb_data *d = id->data;
 102
 103     free(d->dbname);
 104     free(d->mkey);
 105     free(d);
 106     return 0;
 107 }
 108
 109 static krb5_error_code
 110 hdb_get_name(krb5_context context,
 111              krb5_keytab id,
 112              char *name,
 113              size_t namesize)
 114 {
 115     struct hdb_data *d = id->data;
 116
 117     snprintf(name, namesize, "%s%s%s",
 118              d->dbname ? d->dbname : "",
 119              (d->dbname || d->mkey) ? ":" : "",
 120              d->mkey ? d->mkey : "");
 121     return 0;
 122 }
 123
 124 static void
 125 set_config (krb5_context context,
 126             const krb5_config_binding *binding,
 127             const char **dbname,
 128             const char **mkey)
 129 {
 130     *dbname = krb5_config_get_string(context, binding, "dbname", NULL);
 131     *mkey   = krb5_config_get_string(context, binding, "mkey_file", NULL);
 132 }
 133
 134 /*
 135  * try to figure out the database (`dbname') and master-key (`mkey')
 136  * that should be used for `principal'.
 137  */
 138
 139 static void
 140 find_db (krb5_context context,
 141          const char **dbname,
 142          const char **mkey,
 143          krb5_const_principal principal)
 144 {
 145     const krb5_config_binding *top_bind = NULL;
 146     const krb5_config_binding *default_binding = NULL;
 147     const krb5_config_binding *db;
 148     krb5_const_realm realm = krb5_principal_get_realm(context, principal);
 149
 150     *dbname = *mkey = NULL;
 151
 152     while ((db =
 153             krb5_config_get_next(context,
 154                                  NULL,
 155                                  &top_bind,
 156                                  krb5_config_list,
 157                                  "kdc",
 158                                  "database",
 159                                  NULL)) != NULL) {
 160         const char *p;
 161
 162         p = krb5_config_get_string (context, db, "realm", NULL);
 163         if (p == NULL) {
 164             if(default_binding) {
 165                 krb5_warnx(context, "WARNING: more than one realm-less "
 166                            "database specification");
 167                 krb5_warnx(context, "WARNING: using the first encountered");
 168             } else
 169                 default_binding = db;
 170         } else if (strcmp (realm, p) == 0) {
 171             set_config (context, db, dbname, mkey);
 172             break;
 173         }
 174     }
 175     if (*dbname == NULL && default_binding != NULL)
 176         set_config (context, default_binding, dbname, mkey);
 177     if (*dbname == NULL)
 178         *dbname = HDB_DEFAULT_DB;
 179 }
 180
 181 /*
 182  * find the keytab entry in `id' for `principal, kvno, enctype' and return
 183  * it in `entry'.  return 0 or an error code
 184  */
 185
 186 static krb5_error_code
 187 hdb_get_entry(krb5_context context,
 188               krb5_keytab id,
 189               krb5_const_principal principal,
 190               krb5_kvno kvno,
 191               krb5_enctype enctype,
 192               krb5_keytab_entry *entry)
 193 {
 194     hdb_entry_ex ent;
 195     krb5_error_code ret;
 196     struct hdb_data *d = id->data;
 197     int i;
 198     HDB *db;
 199     const char *dbname = d->dbname;
 200     const char *mkey   = d->mkey;
 201
 202     memset(&ent, 0, sizeof(ent));
 203
 204     if (dbname == NULL)
 205         find_db (context, &dbname, &mkey, principal);
 206
 207     ret = hdb_create (context, &db, dbname);
 208     if (ret)
 209         return ret;
 210     ret = hdb_set_master_keyfile (context, db, mkey);
 211     if (ret) {
 212         (*db->hdb_destroy)(context, db);
 213         return ret;
 214     }
 215
 216     ret = (*db->hdb_open)(context, db, O_RDONLY, 0);
 217     if (ret) {
 218         (*db->hdb_destroy)(context, db);
 219         return ret;
 220     }
 221     ret = (*db->hdb_fetch)(context, db, principal,
 222                            HDB_F_DECRYPT|
 223                            HDB_F_GET_CLIENT|HDB_F_GET_SERVER|HDB_F_GET_KRBTGT,
 224                            &ent);
 225
 226     if(ret == HDB_ERR_NOENTRY) {
 227         ret = KRB5_KT_NOTFOUND;
 228         goto out;
 229     }else if(ret)
 230         goto out;
 231
 232     if(kvno && ent.entry.kvno != kvno) {
 233         hdb_free_entry(context, &ent);
 234         ret = KRB5_KT_NOTFOUND;
 235         goto out;
 236     }
 237     if(enctype == 0)
 238         if(ent.entry.keys.len > 0)
 239             enctype = ent.entry.keys.val[0].key.keytype;
 240     ret = KRB5_KT_NOTFOUND;
 241     for(i = 0; i < ent.entry.keys.len; i++) {
 242         if(ent.entry.keys.val[i].key.keytype == enctype) {
 243             krb5_copy_principal(context, principal, &entry->principal);
 244             entry->vno = ent.entry.kvno;
 245             krb5_copy_keyblock_contents(context,
 246                                         &ent.entry.keys.val[i].key,
 247                                         &entry->keyblock);
 248             ret = 0;
 249             break;
 250         }
 251     }
 252     hdb_free_entry(context, &ent);
 253 out:
 254     (*db->hdb_close)(context, db);
 255     (*db->hdb_destroy)(context, db);
 256     return ret;
 257 }
 258
 259 krb5_kt_ops hdb_kt_ops = {
 260     "HDB",
 261     hdb_resolve,
 262     hdb_get_name,
 263     hdb_close,
 264     NULL,               /* destroy */
 265     hdb_get_entry,
 266     NULL,               /* start_seq_get */
 267     NULL,               /* next_entry */
 268     NULL,               /* end_seq_get */
 269     NULL,               /* add */
 270     NULL                /* remove */
 271 };