1 /* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
2 /*
3 * Copyright (C) 1998 by the FundsXpress, INC.
4 *
5 * All rights reserved.
6 *
7 * Export of this software from the United States of America may require
8 * a specific license from the United States Government. It is the
9 * responsibility of any person or organization contemplating export to
10 * obtain such a license before exporting.
11 *
12 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
13 * distribute this software and its documentation for any purpose and
14 * without fee is hereby granted, provided that the above copyright
15 * notice appear in all copies and that both that copyright notice and
16 * this permission notice appear in supporting documentation, and that
17 * the name of FundsXpress. not be used in advertising or publicity pertaining
18 * to distribution of the software without specific, written prior
19 * permission. FundsXpress makes no representations about the suitability of
20 * this software for any purpose. It is provided "as is" without express
21 * or implied warranty.
22 *
23 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
25 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
26 */
27
28 #include "crypto_int.h"
29
30 #define K5CLENGTH 5 /* 32 bit net byte order integer + one byte seed */
31
32 krb5_error_code
krb5int_dk_checksum(const struct krb5_cksumtypes * ctp,krb5_key key,krb5_keyusage usage,const krb5_crypto_iov * data,size_t num_data,krb5_data * output)33 krb5int_dk_checksum(const struct krb5_cksumtypes *ctp,
34 krb5_key key, krb5_keyusage usage,
35 const krb5_crypto_iov *data, size_t num_data,
36 krb5_data *output)
37 {
38 const struct krb5_enc_provider *enc = ctp->enc;
39 krb5_error_code ret;
40 unsigned char constantdata[K5CLENGTH];
41 krb5_data datain;
42 krb5_key kc;
43
44 /* Derive the key. */
45 datain = make_data(constantdata, K5CLENGTH);
46 store_32_be(usage, constantdata);
47 constantdata[4] = (char) 0x99;
48 ret = krb5int_derive_key(enc, NULL, key, &kc, &datain, DERIVE_RFC3961);
49 if (ret)
50 return ret;
51
52 /* Hash the data. */
53 ret = krb5int_hmac(ctp->hash, kc, data, num_data, output);
54 if (ret)
55 memset(output->data, 0, output->length);
56
57 krb5_k_free_key(NULL, kc);
58 return ret;
59 }
60