xref: /freebsd/crypto/heimdal/lib/krb5/generate_seq_number.c (revision 4fe54d7c6acb302aacc6ac18798804b26c882c13)
1 /*
2  * Copyright (c) 1997 - 2001 Kungliga Tekniska H�gskolan
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("$Id: generate_seq_number.c 17442 2006-05-05 09:31:15Z lha $");
37 
38 krb5_error_code KRB5_LIB_FUNCTION
39 krb5_generate_seq_number(krb5_context context,
40 			 const krb5_keyblock *key,
41 			 uint32_t *seqno)
42 {
43     krb5_error_code ret;
44     krb5_keyblock *subkey;
45     uint32_t q;
46     u_char *p;
47     int i;
48 
49     ret = krb5_generate_subkey (context, key, &subkey);
50     if (ret)
51 	return ret;
52 
53     q = 0;
54     for (p = (u_char *)subkey->keyvalue.data, i = 0;
55 	 i < subkey->keyvalue.length;
56 	 ++i, ++p)
57 	q = (q << 8) | *p;
58     q &= 0xffffffff;
59     *seqno = q;
60     krb5_free_keyblock (context, subkey);
61     return 0;
62 }
63