kdc/misc.c

   1 /*
   2  * Copyright (c) 1997 - 2001 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 "kdc_locl.h"
  35
  36 struct timeval _kdc_now;
  37
  38 krb5_error_code
  39 _kdc_db_fetch(krb5_context context,
  40               krb5_kdc_configuration *config,
  41               krb5_const_principal principal,
  42               unsigned flags,
  43               krb5uint32 *kvno_ptr,
  44               HDB **db,
  45               hdb_entry_ex **h)
  46 {
  47     hdb_entry_ex *ent;
  48     krb5_error_code ret = HDB_ERR_NOENTRY;
  49     int i;
  50     unsigned kvno = 0;
  51     krb5_principal enterprise_principal = NULL;
  52     krb5_const_principal princ;
  53
  54     *h = NULL;
  55
  56     if (kvno_ptr != NULL) {
  57         if (*kvno_ptr != 0)
  58             flags |= HDB_F_KVNO_SPECIFIED;
  59         else
  60             flags |= HDB_F_ALL_KVNOS;
  61     }
  62
  63     ent = calloc(1, sizeof (*ent));
  64     if (ent == NULL)
  65         return krb5_enomem(context);
  66
  67     if (principal->name.name_type == KRB5_NT_ENTERPRISE_PRINCIPAL) {
  68         if (principal->name.name_string.len != 1) {
  69             ret = KRB5_PARSE_MALFORMED;
  70             krb5_set_error_message(context, ret,
  71                                    "malformed request: "
  72                                    "enterprise name with %d name components",
  73                                    principal->name.name_string.len);
  74             goto out;
  75         }
  76         ret = krb5_parse_name(context, principal->name.name_string.val[0],
  77                               &enterprise_principal);
  78         if (ret)
  79             goto out;
  80     }
  81
  82     for (i = 0; i < config->num_db; i++) {
  83         ret = config->db[i]->hdb_open(context, config->db[i], O_RDONLY, 0);
  84         if (ret) {
  85             const char *msg = krb5_get_error_message(context, ret);
  86             kdc_log(context, config, 0, "Failed to open database: %s", msg);
  87             krb5_free_error_message(context, msg);
  88             continue;
  89         }
  90
  91         princ = principal;
  92         if (!(config->db[i]->hdb_capability_flags & HDB_CAP_F_HANDLE_ENTERPRISE_PRINCIPAL) && enterprise_principal)
  93             princ = enterprise_principal;
  94
  95         ret = config->db[i]->hdb_fetch_kvno(context,
  96                                             config->db[i],
  97                                             princ,
  98                                             flags | HDB_F_DECRYPT,
  99                                             kvno,
 100                                             ent);
 101         config->db[i]->hdb_close(context, config->db[i]);
 102
 103         switch (ret) {
 104         case HDB_ERR_WRONG_REALM:
 105             /*
 106              * the ent->entry.principal just contains hints for the client
 107              * to retry. This is important for enterprise principal routing
 108              * between trusts.
 109              */
 110             /* fall through */
 111         case 0:
 112             if (db)
 113                 *db = config->db[i];
 114             *h = ent;
 115             ent = NULL;
 116             goto out;
 117
 118         case HDB_ERR_NOENTRY:
 119             /* Check the other databases */
 120             continue;
 121
 122         default:
 123             /*
 124              * This is really important, because errors like
 125              * HDB_ERR_NOT_FOUND_HERE (used to indicate to Samba that
 126              * the RODC on which this code is running does not have
 127              * the key we need, and so a proxy to the KDC is required)
 128              * have specific meaning, and need to be propogated up.
 129              */
 130             goto out;
 131         }
 132     }
 133
 134     if (ret == HDB_ERR_NOENTRY) {
 135         krb5_set_error_message(context, ret, "no such entry found in hdb");
 136     }
 137 out:
 138     krb5_free_principal(context, enterprise_principal);
 139     free(ent);
 140     return ret;
 141 }
 142
 143 void
 144 _kdc_free_ent(krb5_context context, hdb_entry_ex *ent)
 145 {
 146     hdb_free_entry (context, ent);
 147     free (ent);
 148 }
 149
 150 /*
 151  * Use the order list of preferred encryption types and sort the
 152  * available keys and return the most preferred key.
 153  */
 154
 155 krb5_error_code
 156 _kdc_get_preferred_key(krb5_context context,
 157                        krb5_kdc_configuration *config,
 158                        hdb_entry_ex *h,
 159                        const char *name,
 160                        krb5_enctype *enctype,
 161                        Key **key)
 162 {
 163     krb5_error_code ret;
 164     int i;
 165
 166     if (config->use_strongest_server_key) {
 167         const krb5_enctype *p = krb5_kerberos_enctypes(context);
 168
 169         for (i = 0; p[i] != (krb5_enctype)ETYPE_NULL; i++) {
 170             if (krb5_enctype_valid(context, p[i]) != 0 &&
 171                 !_kdc_is_weak_exception(h->entry.principal, p[i]))
 172                 continue;
 173             ret = hdb_enctype2key(context, &h->entry, NULL, p[i], key);
 174             if (ret != 0)
 175                 continue;
 176             if (enctype != NULL)
 177                 *enctype = p[i];
 178             return 0;
 179         }
 180     } else {
 181         *key = NULL;
 182
 183         for (i = 0; i < h->entry.keys.len; i++) {
 184             if (krb5_enctype_valid(context, h->entry.keys.val[i].key.keytype) != 0 &&
 185                 !_kdc_is_weak_exception(h->entry.principal, h->entry.keys.val[i].key.keytype))
 186                 continue;
 187             ret = hdb_enctype2key(context, &h->entry, NULL,
 188                                   h->entry.keys.val[i].key.keytype, key);
 189             if (ret != 0)
 190                 continue;
 191             if (enctype != NULL)
 192                 *enctype = (*key)->key.keytype;
 193             return 0;
 194         }
 195     }
 196
 197     krb5_set_error_message(context, EINVAL,
 198                            "No valid kerberos key found for %s", name);
 199     return EINVAL; /* XXX */
 200 }
 201