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/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* Copyright (C) 1998 by the FundsXpress, INC.
*
* 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 FundsXpress. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. FundsXpress makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#include "k5-int.h"
#include "etypes.h"
#include "dk.h"
#define K5CLENGTH 5 /* 32 bit net byte order integer + one byte seed */
/*
* Derive the key for checksum calculation.
* This is only called (currently) for SHA1-DES3
* checksum types.
*
* The primary benefit here is that a KEF template
* is created for use when doing the HMAC operation which
* saves ALOT of computation cycles and improves performance.
*/
static krb5_error_code
derive_cksum_key(krb5_context context,
struct krb5_enc_provider *enc,
const krb5_keyblock *key,
krb5_keyusage usage,
krb5_keyblock **outkey)
{
krb5_error_code ret = 0;
krb5_keyblock *cached_key = NULL;
krb5_data d1;
unsigned char constantdata[K5CLENGTH];
cached_key = find_derived_key(usage, DK_CKSUM_KEY_BYTE,
(krb5_keyblock *)key);
if (cached_key)
*outkey = cached_key;
else {
*outkey = krb5_create_derived_keyblock(key->length);
if (*outkey == NULL)
return (ENOMEM);
constantdata[0] = (usage>>24)&0xff;
constantdata[1] = (usage>>16)&0xff;
constantdata[2] = (usage>>8)&0xff;
constantdata[3] = usage&0xff;
constantdata[4] = DK_CKSUM_KEY_BYTE;
d1.data = (char *)constantdata;
d1.length = sizeof(constantdata);
ret = krb5_derive_key(context, enc, key,
*outkey, &d1);
if (ret) {
krb5_free_keyblock(context, *outkey);
*outkey = NULL;
return (ret);
}
#ifdef _KERNEL
/*
* By default, derived keys get the "mech_type"
* that was associated with their parent.
* we need to switch the mech_type to correspond
* to the checksum mech type.
*/
if (ret == 0 &&
(*outkey)->kef_mt != context->kef_cksum_mt) {
(*outkey)->kef_mt = context->kef_cksum_mt;
if ((*outkey)->key_tmpl != NULL) {
crypto_destroy_ctx_template((*outkey)->key_tmpl);
(*outkey)->key_tmpl = NULL;
}
ret = update_key_template(*outkey);
}
#endif /* _KERNEL */
if (ret == 0)
ret = add_derived_key((krb5_keyblock *)key, usage,
DK_CKSUM_KEY_BYTE,
*outkey);
}
finish:
KRB5_LOG0(KRB5_INFO, "derive_cksum_key() end.");
return (ret);
}
/* ARGSUSED */
krb5_error_code
krb5_dk_make_checksum(context, hash, key, usage, input, output)
krb5_context context;
krb5_const struct krb5_hash_provider *hash;
krb5_const krb5_keyblock *key;
krb5_keyusage usage;
krb5_const krb5_data *input;
krb5_data *output;
{
int i;
krb5_error_code ret;
krb5_keyblock *cksum_key = NULL;
struct krb5_enc_provider *enc = NULL;
KRB5_LOG0(KRB5_INFO, "krb5_dk_make_checksum() start");
for (i=0; i<krb5_enctypes_length; i++) {
if (krb5_enctypes_list[i].etype == key->enctype)
break;
}
if (i == krb5_enctypes_length) {
KRB5_LOG(KRB5_ERR, "krb5_ck_make_checksum bad enctype: %d",
key->enctype);
return(KRB5_BAD_ENCTYPE);
}
enc = (struct krb5_enc_provider *)krb5_enctypes_list[i].enc;
#ifdef _KERNEL
if (key->kef_key.ck_data == NULL &&
(ret = init_key_kef(krb5_enctypes_list[i].kef_cipher_mt,
(krb5_keyblock *)key)))
goto cleanup;
#endif
ret = derive_cksum_key(context, enc, key, usage, &cksum_key);
if (ret != 0)
goto cleanup;
#ifdef _KERNEL
if ((ret = krb5_hmac(context, (krb5_keyblock *)cksum_key,
input, output))) {
KRB5_LOG(KRB5_ERR, "krb5_hmac error: %0x", ret);
(void) memset(output->data, 0, output->length);
}
#else
if ((ret = krb5_hmac(context, hash, cksum_key, 1, input, output)) != 0) {
KRB5_LOG(KRB5_ERR, "krb5_hmac error: %0x", ret);
(void) memset(output->data, 0, output->length);
}
#endif /* _KERNEL */
cleanup:
KRB5_LOG0(KRB5_INFO, "krb5_dk_make_checksum() end");
return(ret);
}
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