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 static int
  37 name_type_ok(krb5_context context,
  38              krb5_kdc_configuration *config,
  39              krb5_const_principal principal)
  40 {
  41     int nt = krb5_principal_get_type(context, principal);
  42
  43     if (!krb5_principal_is_krbtgt(context, principal))
  44         return 1;
  45     if (nt == KRB5_NT_SRV_INST || nt == KRB5_NT_UNKNOWN)
  46         return 1;
  47     if (config->strict_nametypes == 0)
  48         return 1;
  49     return 0;
  50 }
  51
  52 struct timeval _kdc_now;
  53
  54 static krb5_error_code
  55 synthesize_hdb_close(krb5_context context, struct HDB *db)
  56 {
  57     (void) context;
  58     (void) db;
  59     return 0;
  60 }
  61
  62 /*
  63  * Synthesize an HDB entry suitable for PKINIT and only PKINIT.
  64  */
  65 static krb5_error_code
  66 synthesize_client(krb5_context context,
  67                   krb5_kdc_configuration *config,
  68                   krb5_const_principal princ,
  69                   HDB **db,
  70                   hdb_entry_ex **h)
  71 {
  72     static HDB null_db;
  73     krb5_error_code ret;
  74     hdb_entry_ex *e;
  75
  76     /* Hope this works! */
  77     null_db.hdb_destroy = synthesize_hdb_close;
  78     null_db.hdb_close = synthesize_hdb_close;
  79     if (db)
  80         *db = &null_db;
  81
  82     ret = (e = calloc(1, sizeof(*e))) ? 0 : krb5_enomem(context);
  83     if (ret == 0) {
  84         e->entry.flags.client = 1;
  85         e->entry.flags.immutable = 1;
  86         e->entry.flags.virtual = 1;
  87         e->entry.flags.synthetic = 1;
  88         e->entry.flags.do_not_store = 1;
  89         e->entry.kvno = 1;
  90         e->entry.keys.len = 0;
  91         e->entry.keys.val = NULL;
  92         e->entry.created_by.time = time(NULL);
  93         e->entry.modified_by = NULL;
  94         e->entry.valid_start = NULL;
  95         e->entry.valid_end = NULL;
  96         e->entry.pw_end = NULL;
  97         e->entry.etypes = NULL;
  98         e->entry.generation = NULL;
  99         e->entry.extensions = NULL;
 100     }
 101     if (ret == 0)
 102         ret = (e->entry.max_renew = calloc(1, sizeof(*e->entry.max_renew))) ?
 103             0 : krb5_enomem(context);
 104     if (ret == 0)
 105         ret = (e->entry.max_life = calloc(1, sizeof(*e->entry.max_life))) ?
 106             0 : krb5_enomem(context);
 107     if (ret == 0)
 108         ret = krb5_copy_principal(context, princ, &e->entry.principal);
 109     if (ret == 0)
 110         ret = krb5_copy_principal(context, princ, &e->entry.created_by.principal);
 111     if (ret == 0) {
 112         /*
 113          * We can't check OCSP in the TGS path, so we can't let tickets for
 114          * synthetic principals live very long.
 115          */
 116         *(e->entry.max_renew) = config->synthetic_clients_max_renew;
 117         *(e->entry.max_life) = config->synthetic_clients_max_life;
 118         *h = e;
 119     } else {
 120         hdb_free_entry(context, e);
 121     }
 122     return ret;
 123 }
 124
 125 krb5_error_code
 126 _kdc_db_fetch(krb5_context context,
 127               krb5_kdc_configuration *config,
 128               krb5_const_principal principal,
 129               unsigned flags,
 130               krb5uint32 *kvno_ptr,
 131               HDB **db,
 132               hdb_entry_ex **h)
 133 {
 134     hdb_entry_ex *ent = NULL;
 135     krb5_error_code ret = HDB_ERR_NOENTRY;
 136     int i;
 137     unsigned kvno = 0;
 138     krb5_principal enterprise_principal = NULL;
 139     krb5_const_principal princ;
 140
 141     *h = NULL;
 142
 143     if (!name_type_ok(context, config, principal))
 144         return HDB_ERR_NOENTRY;
 145
 146     flags |= HDB_F_DECRYPT;
 147     if (kvno_ptr != NULL && *kvno_ptr != 0) {
 148         kvno = *kvno_ptr;
 149         flags |= HDB_F_KVNO_SPECIFIED;
 150     } else {
 151         flags |= HDB_F_ALL_KVNOS;
 152     }
 153
 154     ent = calloc(1, sizeof (*ent));
 155     if (ent == NULL)
 156         return krb5_enomem(context);
 157
 158     if (principal->name.name_type == KRB5_NT_ENTERPRISE_PRINCIPAL) {
 159         if (principal->name.name_string.len != 1) {
 160             ret = KRB5_PARSE_MALFORMED;
 161             krb5_set_error_message(context, ret,
 162                                    "malformed request: "
 163                                    "enterprise name with %d name components",
 164                                    principal->name.name_string.len);
 165             goto out;
 166         }
 167         ret = krb5_parse_name(context, principal->name.name_string.val[0],
 168                               &enterprise_principal);
 169         if (ret)
 170             goto out;
 171     }
 172
 173     for (i = 0; i < config->num_db; i++) {
 174         HDB *curdb = config->db[i];
 175
 176         if (db)
 177             *db = curdb;
 178
 179         ret = curdb->hdb_open(context, curdb, O_RDONLY, 0);
 180         if (ret) {
 181             const char *msg = krb5_get_error_message(context, ret);
 182             kdc_log(context, config, 0, "Failed to open database: %s", msg);
 183             krb5_free_error_message(context, msg);
 184             continue;
 185         }
 186
 187         princ = principal;
 188         if (!(curdb->hdb_capability_flags & HDB_CAP_F_HANDLE_ENTERPRISE_PRINCIPAL) && enterprise_principal)
 189             princ = enterprise_principal;
 190
 191         ret = hdb_fetch_kvno(context, curdb, princ, flags, 0, 0, kvno, ent);
 192         curdb->hdb_close(context, curdb);
 193
 194         if (ret == HDB_ERR_NOENTRY)
 195             continue; /* Check the other databases */
 196
 197         /*
 198          * This is really important, because errors like
 199          * HDB_ERR_NOT_FOUND_HERE (used to indicate to Samba that
 200          * the RODC on which this code is running does not have
 201          * the key we need, and so a proxy to the KDC is required)
 202          * have specific meaning, and need to be propogated up.
 203          */
 204         break;
 205     }
 206
 207     switch (ret) {
 208     case HDB_ERR_WRONG_REALM:
 209     case 0:
 210         /*
 211          * the ent->entry.principal just contains hints for the client
 212          * to retry. This is important for enterprise principal routing
 213          * between trusts.
 214          */
 215         *h = ent;
 216         ent = NULL;
 217         break;
 218
 219     case HDB_ERR_NOENTRY:
 220         if (db)
 221             *db = NULL;
 222         if ((flags & HDB_F_GET_CLIENT) && (flags & HDB_F_SYNTHETIC_OK) &&
 223             config->synthetic_clients) {
 224             ret = synthesize_client(context, config, principal, db, h);
 225             if (ret) {
 226                 krb5_set_error_message(context, ret, "could not synthesize "
 227                                        "HDB client principal entry");
 228                 ret = HDB_ERR_NOENTRY;
 229                 krb5_prepend_error_message(context, ret, "no such entry found in hdb");
 230             }
 231         } else {
 232             krb5_set_error_message(context, ret, "no such entry found in hdb");
 233         }
 234         break;
 235
 236     default:
 237         if (db)
 238             *db = NULL;
 239         break;
 240     }
 241
 242 out:
 243     krb5_free_principal(context, enterprise_principal);
 244     free(ent);
 245     return ret;
 246 }
 247
 248 void
 249 _kdc_free_ent(krb5_context context, hdb_entry_ex *ent)
 250 {
 251     hdb_free_entry (context, ent);
 252     free (ent);
 253 }
 254
 255 /*
 256  * Use the order list of preferred encryption types and sort the
 257  * available keys and return the most preferred key.
 258  */
 259
 260 krb5_error_code
 261 _kdc_get_preferred_key(krb5_context context,
 262                        krb5_kdc_configuration *config,
 263                        hdb_entry_ex *h,
 264                        const char *name,
 265                        krb5_enctype *enctype,
 266                        Key **key)
 267 {
 268     krb5_error_code ret;
 269     int i;
 270
 271     if (config->use_strongest_server_key) {
 272         const krb5_enctype *p = krb5_kerberos_enctypes(context);
 273
 274         for (i = 0; p[i] != (krb5_enctype)ETYPE_NULL; i++) {
 275             if (krb5_enctype_valid(context, p[i]) != 0 &&
 276                 !_kdc_is_weak_exception(h->entry.principal, p[i]))
 277                 continue;
 278             ret = hdb_enctype2key(context, &h->entry, NULL, p[i], key);
 279             if (ret != 0)
 280                 continue;
 281             if (enctype != NULL)
 282                 *enctype = p[i];
 283             return 0;
 284         }
 285     } else {
 286         *key = NULL;
 287
 288         for (i = 0; i < h->entry.keys.len; i++) {
 289             if (krb5_enctype_valid(context, h->entry.keys.val[i].key.keytype) != 0 &&
 290                 !_kdc_is_weak_exception(h->entry.principal, h->entry.keys.val[i].key.keytype))
 291                 continue;
 292             ret = hdb_enctype2key(context, &h->entry, NULL,
 293                                   h->entry.keys.val[i].key.keytype, key);
 294             if (ret != 0)
 295                 continue;
 296             if (enctype != NULL)
 297                 *enctype = (*key)->key.keytype;
 298             return 0;
 299         }
 300     }
 301
 302     krb5_set_error_message(context, EINVAL,
 303                            "No valid kerberos key found for %s", name);
 304     return EINVAL; /* XXX */
 305 }
 306