1/*
2 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
3 * Use is subject to license terms.
4 */
5
6
7/*
8 * Copyright (C) 1998 by the FundsXpress, INC.
9 *
10 * All rights reserved.
11 *
12 * Export of this software from the United States of America may require
13 * a specific license from the United States Government.  It is the
14 * responsibility of any person or organization contemplating export to
15 * obtain such a license before exporting.
16 *
17 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
18 * distribute this software and its documentation for any purpose and
19 * without fee is hereby granted, provided that the above copyright
20 * notice appear in all copies and that both that copyright notice and
21 * this permission notice appear in supporting documentation, and that
22 * the name of FundsXpress. not be used in advertising or publicity pertaining
23 * to distribution of the software without specific, written prior
24 * permission.  FundsXpress makes no representations about the suitability of
25 * this software for any purpose.  It is provided "as is" without express
26 * or implied warranty.
27 *
28 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
29 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
30 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
31 */
32
33#include "k5-int.h"
34#include "cksumtypes.h"
35
36krb5_error_code KRB5_CALLCONV
37krb5_c_verify_checksum(krb5_context context, const krb5_keyblock *key,
38		       krb5_keyusage usage, const krb5_data *data,
39		       const krb5_checksum *cksum, krb5_boolean *valid)
40{
41    int i;
42    size_t hashsize;
43    krb5_error_code ret;
44    krb5_data indata;
45    krb5_checksum computed;
46
47    for (i=0; i<krb5_cksumtypes_length; i++) {
48	if (krb5_cksumtypes_list[i].ctype == cksum->checksum_type)
49	    break;
50    }
51
52    if (i == krb5_cksumtypes_length)
53	return(KRB5_BAD_ENCTYPE);
54
55    /* if there's actually a verify function, call it */
56
57    indata.length = cksum->length;
58    indata.data = (char *) cksum->contents;
59    *valid = 0;
60
61    if (krb5_cksumtypes_list[i].keyhash &&
62	krb5_cksumtypes_list[i].keyhash->verify)
63	return((*(krb5_cksumtypes_list[i].keyhash->verify))(
64		context, key, usage, 0, data, &indata, valid));
65
66    /* otherwise, make the checksum again, and compare */
67
68    if ((ret = krb5_c_checksum_length(context, cksum->checksum_type, &hashsize)))
69	return(ret);
70
71    if (cksum->length != hashsize)
72	return(KRB5_BAD_MSIZE);
73
74    computed.length = hashsize;
75
76    if ((ret = krb5_c_make_checksum(context, cksum->checksum_type, key, usage,
77				   data, &computed))) {
78	FREE(computed.contents, computed.length);
79	return(ret);
80    }
81
82    *valid = (memcmp(computed.contents, cksum->contents, hashsize) == 0);
83
84    FREE(computed.contents, computed.length);
85
86    return(0);
87}
88