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/*
* lib/crypto/keyhash_provider/hmac_md5.c
*
* Copyright 2001, 2009 by the Massachusetts Institute of Technology.
* All Rights Reserved.
*
* Export of this software from the United States of America may
* require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. Furthermore if you modify this software you must label
* your software as modified software and not distribute it in such a
* fashion that it might be confused with the original M.I.T. software.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
*
* Implementation of the Microsoft hmac-md5 checksum type.
* Implemented based on draft-brezak-win2k-krb-rc4-hmac-03
*/
#include "k5-int.h"
#include "keyhash_provider.h"
#include "arcfour-int.h"
#include "rsa-md5.h"
#include "hash_provider.h"
#include "../aead.h"
static krb5_error_code
k5_hmac_md5_hash (const krb5_keyblock *key, krb5_keyusage usage,
const krb5_data *iv,
const krb5_data *input, krb5_data *output)
{
krb5_keyusage ms_usage;
krb5_error_code ret;
krb5_keyblock ks;
krb5_data ds, ks_constant, md5tmp;
krb5_MD5_CTX ctx;
char t[4];
ds.length = key->length;
ks.length = key->length;
ds.data = malloc(ds.length);
if (ds.data == NULL)
return ENOMEM;
ks.contents = (void *) ds.data;
ks_constant.data = "signaturekey";
ks_constant.length = strlen(ks_constant.data)+1; /* Including null*/
ret = krb5_hmac( &krb5int_hash_md5, key, 1,
&ks_constant, &ds);
if (ret)
goto cleanup;
krb5_MD5Init (&ctx);
ms_usage = krb5int_arcfour_translate_usage (usage);
store_32_le(ms_usage, t);
krb5_MD5Update (&ctx, (unsigned char * ) &t, 4);
krb5_MD5Update (&ctx, (unsigned char *) input-> data,
(unsigned int) input->length );
krb5_MD5Final(&ctx);
md5tmp.data = (void *) ctx.digest;
md5tmp.length = 16;
ret = krb5_hmac ( &krb5int_hash_md5, &ks, 1, &md5tmp,
output);
cleanup:
memset(&ctx, 0, sizeof(ctx));
memset (ks.contents, 0, ks.length);
free (ks.contents);
return ret;
}
static krb5_error_code
k5_hmac_md5_hash_iov (const krb5_keyblock *key, krb5_keyusage usage,
const krb5_data *iv,
const krb5_crypto_iov *data, size_t num_data,
krb5_data *output)
{
krb5_keyusage ms_usage;
krb5_error_code ret;
krb5_keyblock ks;
krb5_data ds, ks_constant, md5tmp;
krb5_MD5_CTX ctx;
char t[4];
size_t i;
ds.length = key->length;
ks.length = key->length;
ds.data = malloc(ds.length);
if (ds.data == NULL)
return ENOMEM;
ks.contents = (void *) ds.data;
ks_constant.data = "signaturekey";
ks_constant.length = strlen(ks_constant.data)+1; /* Including null*/
ret = krb5_hmac( &krb5int_hash_md5, key, 1,
&ks_constant, &ds);
if (ret)
goto cleanup;
krb5_MD5Init (&ctx);
ms_usage = krb5int_arcfour_translate_usage (usage);
store_32_le(ms_usage, t);
krb5_MD5Update (&ctx, (unsigned char * ) &t, 4);
for (i = 0; i < num_data; i++) {
const krb5_crypto_iov *iov = &data[i];
if (SIGN_IOV(iov))
krb5_MD5Update (&ctx, (unsigned char *)iov->data.data,
(unsigned int)iov->data.length);
}
krb5_MD5Final(&ctx);
md5tmp.data = (void *) ctx.digest;
md5tmp.length = 16;
ret = krb5_hmac ( &krb5int_hash_md5, &ks, 1, &md5tmp,
output);
cleanup:
memset(&ctx, 0, sizeof(ctx));
memset (ks.contents, 0, ks.length);
free (ks.contents);
return ret;
}
const struct krb5_keyhash_provider krb5int_keyhash_hmac_md5 = {
16,
k5_hmac_md5_hash,
NULL, /*checksum again*/
k5_hmac_md5_hash_iov,
NULL /*checksum again */
};
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