1 /* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
2 /* lib/crypto/krb/prf_cmac.c - CMAC-based PRF */
3 /*
4 * Copyright (C) 2010 by the Massachusetts Institute of Technology.
5 * All rights reserved.
6 *
7 * Export of this software from the United States of America may
8 * require a specific license from the United States Government.
9 * It is the responsibility of any person or organization contemplating
10 * export to 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 M.I.T. not be used in advertising or publicity pertaining
18 * to distribution of the software without specific, written prior
19 * permission. Furthermore if you modify this software you must label
20 * your software as modified software and not distribute it in such a
21 * fashion that it might be confused with the original M.I.T. software.
22 * M.I.T. makes no representations about the suitability of
23 * this software for any purpose. It is provided "as is" without express
24 * or implied warranty.
25 */
26
27 #include "crypto_int.h"
28
29 krb5_error_code
krb5int_dk_cmac_prf(const struct krb5_keytypes * ktp,krb5_key key,const krb5_data * in,krb5_data * out)30 krb5int_dk_cmac_prf(const struct krb5_keytypes *ktp, krb5_key key,
31 const krb5_data *in, krb5_data *out)
32 {
33 krb5_crypto_iov iov;
34 krb5_data prfconst = make_data("prf", 3);
35 krb5_key kp = NULL;
36 krb5_error_code ret;
37
38 if (ktp->prf_length != ktp->enc->block_size)
39 return KRB5_BAD_MSIZE;
40
41 iov.flags = KRB5_CRYPTO_TYPE_DATA;
42 iov.data = *in;
43
44 /* Derive a key using the PRF constant. */
45 ret = krb5int_derive_key(ktp->enc, NULL, key, &kp, &prfconst,
46 DERIVE_SP800_108_CMAC);
47 if (ret != 0)
48 goto cleanup;
49
50 /* PRF is CMAC of input */
51 ret = krb5int_cmac_checksum(ktp->enc, kp, &iov, 1, out);
52 if (ret != 0)
53 goto cleanup;
54
55 cleanup:
56 krb5_k_free_key(NULL, kp);
57 return ret;
58 }
59