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             kvno = *kvno_ptr;
  59             flags |= HDB_F_KVNO_SPECIFIED;
  60         } else {
  61             flags |= HDB_F_ALL_KVNOS;
  62         }
  63     }
  64
  65     ent = calloc(1, sizeof (*ent));
  66     if (ent == NULL)
  67         return krb5_enomem(context);
  68
  69     if (principal->name.name_type == KRB5_NT_ENTERPRISE_PRINCIPAL) {
  70         if (principal->name.name_string.len != 1) {
  71             ret = KRB5_PARSE_MALFORMED;
  72             krb5_set_error_message(context, ret,
  73                                    "malformed request: "
  74                                    "enterprise name with %d name components",
  75                                    principal->name.name_string.len);
  76             goto out;
  77         }
  78         ret = krb5_parse_name(context, principal->name.name_string.val[0],
  79                               &enterprise_principal);
  80         if (ret)
  81             goto out;
  82     }
  83
  84     for (i = 0; i < config->num_db; i++) {
  85         ret = config->db[i]->hdb_open(context, config->db[i], O_RDONLY, 0);
  86         if (ret) {
  87             const char *msg = krb5_get_error_message(context, ret);
  88             kdc_log(context, config, 0, "Failed to open database: %s", msg);
  89             krb5_free_error_message(context, msg);
  90             continue;
  91         }
  92
  93         princ = principal;
  94         if (!(config->db[i]->hdb_capability_flags & HDB_CAP_F_HANDLE_ENTERPRISE_PRINCIPAL) && enterprise_principal)
  95             princ = enterprise_principal;
  96
  97         ret = config->db[i]->hdb_fetch_kvno(context,
  98                                             config->db[i],
  99                                             princ,
 100                                             flags | HDB_F_DECRYPT,
 101                                             kvno,
 102                                             ent);
 103         config->db[i]->hdb_close(context, config->db[i]);
 104
 105         switch (ret) {
 106         case HDB_ERR_WRONG_REALM:
 107             /*
 108              * the ent->entry.principal just contains hints for the client
 109              * to retry. This is important for enterprise principal routing
 110              * between trusts.
 111              */
 112             /* fall through */
 113         case 0:
 114             if (db)
 115                 *db = config->db[i];
 116             *h = ent;
 117             ent = NULL;
 118             goto out;
 119
 120         case HDB_ERR_NOENTRY:
 121             /* Check the other databases */
 122             continue;
 123
 124         default:
 125             /*
 126              * This is really important, because errors like
 127              * HDB_ERR_NOT_FOUND_HERE (used to indicate to Samba that
 128              * the RODC on which this code is running does not have
 129              * the key we need, and so a proxy to the KDC is required)
 130              * have specific meaning, and need to be propogated up.
 131              */
 132             goto out;
 133         }
 134     }
 135
 136     if (ret == HDB_ERR_NOENTRY) {
 137         krb5_set_error_message(context, ret, "no such entry found in hdb");
 138     }
 139 out:
 140     krb5_free_principal(context, enterprise_principal);
 141     free(ent);
 142     return ret;
 143 }
 144
 145 void
 146 _kdc_free_ent(krb5_context context, hdb_entry_ex *ent)
 147 {
 148     hdb_free_entry (context, ent);
 149     free (ent);
 150 }
 151
 152 /*
 153  * Use the order list of preferred encryption types and sort the
 154  * available keys and return the most preferred key.
 155  */
 156
 157 krb5_error_code
 158 _kdc_get_preferred_key(krb5_context context,
 159                        krb5_kdc_configuration *config,
 160                        hdb_entry_ex *h,
 161                        const char *name,
 162                        krb5_enctype *enctype,
 163                        Key **key)
 164 {
 165     krb5_error_code ret;
 166     int i;
 167
 168     if (config->use_strongest_server_key) {
 169         const krb5_enctype *p = krb5_kerberos_enctypes(context);
 170
 171         for (i = 0; p[i] != (krb5_enctype)ETYPE_NULL; i++) {
 172             if (krb5_enctype_valid(context, p[i]) != 0 &&
 173                 !_kdc_is_weak_exception(h->entry.principal, p[i]))
 174                 continue;
 175             ret = hdb_enctype2key(context, &h->entry, NULL, p[i], key);
 176             if (ret != 0)
 177                 continue;
 178             if (enctype != NULL)
 179                 *enctype = p[i];
 180             return 0;
 181         }
 182     } else {
 183         *key = NULL;
 184
 185         for (i = 0; i < h->entry.keys.len; i++) {
 186             if (krb5_enctype_valid(context, h->entry.keys.val[i].key.keytype) != 0 &&
 187                 !_kdc_is_weak_exception(h->entry.principal, h->entry.keys.val[i].key.keytype))
 188                 continue;
 189             ret = hdb_enctype2key(context, &h->entry, NULL,
 190                                   h->entry.keys.val[i].key.keytype, key);
 191             if (ret != 0)
 192                 continue;
 193             if (enctype != NULL)
 194                 *enctype = (*key)->key.keytype;
 195             return 0;
 196         }
 197     }
 198
 199     krb5_set_error_message(context, EINVAL,
 200                            "No valid kerberos key found for %s", name);
 201     return EINVAL; /* XXX */
 202 }
 203