crypto/dist/heimdal/lib/krb5/generate_seq_number.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 <krb5_locl.h>
  35
  36 __RCSID("$Heimdal: generate_seq_number.c 17442 2006-05-05 09:31:15Z lha $"
  37         "$NetBSD$");
  38
  39 krb5_error_code KRB5_LIB_FUNCTION
  40 krb5_generate_seq_number(krb5_context context,
  41                          const krb5_keyblock *key,
  42                          uint32_t *seqno)
  43 {
  44     krb5_error_code ret;
  45     krb5_keyblock *subkey;
  46     uint32_t q;
  47     u_char *p;
  48     int i;
  49
  50     ret = krb5_generate_subkey (context, key, &subkey);
  51     if (ret)
  52         return ret;
  53
  54     q = 0;
  55     for (p = (u_char *)subkey->keyvalue.data, i = 0;
  56          i < subkey->keyvalue.length;
  57          ++i, ++p)
  58         q = (q << 8) | *p;
  59     q &= 0xffffffff;
  60     *seqno = q;
  61     krb5_free_keyblock (context, subkey);
  62     return 0;
  63 }