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/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
* 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 "crypto_int.h"
static const unsigned char kerberos[] = "kerberos";
#define kerberos_len (sizeof(kerberos)-1)
krb5_error_code
krb5int_dk_string_to_key(const struct krb5_keytypes *ktp,
const krb5_data *string, const krb5_data *salt,
const krb5_data *parms, krb5_keyblock *keyblock)
{
krb5_error_code ret;
size_t keybytes, keylength, concatlen;
unsigned char *concat = NULL, *foldstring = NULL, *foldkeydata = NULL;
krb5_data indata;
krb5_keyblock foldkeyblock;
krb5_key foldkey = NULL;
/* keyblock->length is checked by krb5int_derive_key. */
keybytes = ktp->enc->keybytes;
keylength = ktp->enc->keylength;
concatlen = string->length + (salt ? salt->length : 0);
concat = k5alloc(concatlen, &ret);
if (ret != 0)
goto cleanup;
foldstring = k5alloc(keybytes, &ret);
if (ret != 0)
goto cleanup;
foldkeydata = k5alloc(keylength, &ret);
if (ret != 0)
goto cleanup;
/* construct input string ( = string + salt), fold it, make_key it */
memcpy(concat, string->data, string->length);
if (salt)
memcpy(concat + string->length, salt->data, salt->length);
krb5int_nfold(concatlen*8, concat, keybytes*8, foldstring);
indata.length = keybytes;
indata.data = (char *) foldstring;
foldkeyblock.length = keylength;
foldkeyblock.contents = foldkeydata;
foldkeyblock.enctype = ktp->etype;
ret = ktp->rand2key(&indata, &foldkeyblock);
if (ret != 0)
goto cleanup;
ret = krb5_k_create_key(NULL, &foldkeyblock, &foldkey);
if (ret != 0)
goto cleanup;
/* now derive the key from this one */
indata.length = kerberos_len;
indata.data = (char *) kerberos;
ret = krb5int_derive_keyblock(ktp->enc, foldkey, keyblock, &indata,
DERIVE_RFC3961);
if (ret != 0)
memset(keyblock->contents, 0, keyblock->length);
cleanup:
zapfree(concat, concatlen);
zapfree(foldstring, keybytes);
zapfree(foldkeydata, keylength);
krb5_k_free_key(NULL, foldkey);
return ret;
}
#define MAX_ITERATION_COUNT 0x1000000L
static krb5_error_code
pbkdf2_string_to_key(const struct krb5_keytypes *ktp, const krb5_data *string,
const krb5_data *salt, const krb5_data *pepper,
const krb5_data *params, krb5_keyblock *key,
enum deriv_alg deriv_alg, unsigned long def_iter_count)
{
unsigned long iter_count;
krb5_data out;
static const krb5_data usage = { KV5M_DATA, 8, "kerberos" };
krb5_key tempkey = NULL;
krb5_error_code err;
krb5_data sandp = empty_data();
if (params) {
unsigned char *p = (unsigned char *) params->data;
if (params->length != 4)
return KRB5_ERR_BAD_S2K_PARAMS;
/* The first two need casts in case 'int' is 16 bits. */
iter_count = load_32_be(p);
if (iter_count == 0) {
iter_count = (1UL << 16) << 16;
if (((iter_count >> 16) >> 16) != 1)
return KRB5_ERR_BAD_S2K_PARAMS;
}
} else
iter_count = def_iter_count;
/* This is not a protocol specification constraint; this is an
implementation limit, which should eventually be controlled by
a config file. */
if (iter_count >= MAX_ITERATION_COUNT)
return KRB5_ERR_BAD_S2K_PARAMS;
/* Use the output keyblock contents for temporary space. */
out.data = (char *) key->contents;
out.length = key->length;
if (out.length != 16 && out.length != 32)
return KRB5_CRYPTO_INTERNAL;
if (pepper != NULL) {
err = alloc_data(&sandp, pepper->length + 1 + salt->length);
if (err)
return err;
memcpy(sandp.data, pepper->data, pepper->length);
sandp.data[pepper->length] = '\0';
memcpy(&sandp.data[pepper->length + 1], salt->data, salt->length);
salt = &sandp;
}
err = krb5int_pbkdf2_hmac_sha1 (&out, iter_count, string, salt);
if (err)
goto cleanup;
err = krb5_k_create_key (NULL, key, &tempkey);
if (err)
goto cleanup;
err = krb5int_derive_keyblock(ktp->enc, tempkey, key, &usage, deriv_alg);
cleanup:
if (sandp.data)
free(sandp.data);
if (err)
memset (out.data, 0, out.length);
krb5_k_free_key (NULL, tempkey);
return err;
}
krb5_error_code
krb5int_aes_string_to_key(const struct krb5_keytypes *ktp,
const krb5_data *string,
const krb5_data *salt,
const krb5_data *params,
krb5_keyblock *key)
{
return pbkdf2_string_to_key(ktp, string, salt, NULL, params, key,
DERIVE_RFC3961, 4096);
}
krb5_error_code
krb5int_camellia_string_to_key(const struct krb5_keytypes *ktp,
const krb5_data *string,
const krb5_data *salt,
const krb5_data *params,
krb5_keyblock *key)
{
krb5_data pepper = string2data(ktp->name);
return pbkdf2_string_to_key(ktp, string, salt, &pepper, params, key,
DERIVE_SP800_108_CMAC, 32768);
}
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