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/*
* Copyright (C) 2008 by the Massachusetts Institute of Technology.
* Copyright 1995 by Richard P. Basch. All Rights Reserved.
* Copyright 1995 by Lehman Brothers, 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 Richard P. Basch, Lehman Brothers and M.I.T. not be used
* in advertising or publicity pertaining to distribution of the software
* without specific, written prior permission. Richard P. Basch,
* Lehman Brothers and M.I.T. make no representations about the suitability
* of this software for any purpose. It is provided "as is" without
* express or implied warranty.
*/
#include "des_int.h"
#include "f_tables.h"
#include "aead.h"
void
krb5int_des3_cbc_encrypt_iov(krb5_crypto_iov *data,
unsigned long num_data,
const mit_des_key_schedule ks1,
const mit_des_key_schedule ks2,
const mit_des_key_schedule ks3,
mit_des_cblock ivec)
{
unsigned DES_INT32 left, right;
const unsigned DES_INT32 *kp1, *kp2, *kp3;
const unsigned char *ip;
unsigned char *op;
struct iov_block_state input_pos, output_pos;
unsigned char iblock[MIT_DES_BLOCK_LENGTH];
unsigned char oblock[MIT_DES_BLOCK_LENGTH];
IOV_BLOCK_STATE_INIT(&input_pos);
IOV_BLOCK_STATE_INIT(&output_pos);
/*
* Get key pointer here. This won't need to be reinitialized
*/
kp1 = (const unsigned DES_INT32 *)ks1;
kp2 = (const unsigned DES_INT32 *)ks2;
kp3 = (const unsigned DES_INT32 *)ks3;
/*
* Initialize left and right with the contents of the initial
* vector.
*/
if (ivec != NULL)
ip = ivec;
else
ip = mit_des_zeroblock;
GET_HALF_BLOCK(left, ip);
GET_HALF_BLOCK(right, ip);
/*
* Suitably initialized, now work the length down 8 bytes
* at a time.
*/
for (;;) {
unsigned DES_INT32 temp;
ip = iblock;
op = oblock;
if (!krb5int_c_iov_get_block(iblock, MIT_DES_BLOCK_LENGTH, data, num_data, &input_pos))
break;
if (input_pos.iov_pos == num_data)
break;
GET_HALF_BLOCK(temp, ip);
left ^= temp;
GET_HALF_BLOCK(temp, ip);
right ^= temp;
/*
* Encrypt what we have
*/
DES_DO_ENCRYPT(left, right, kp1);
DES_DO_DECRYPT(left, right, kp2);
DES_DO_ENCRYPT(left, right, kp3);
/*
* Copy the results out
*/
PUT_HALF_BLOCK(left, op);
PUT_HALF_BLOCK(right, op);
krb5int_c_iov_put_block(data, num_data, oblock, MIT_DES_BLOCK_LENGTH, &output_pos);
}
if (ivec != NULL)
memcpy(ivec, oblock, MIT_DES_BLOCK_LENGTH);
}
void
krb5int_des3_cbc_decrypt_iov(krb5_crypto_iov *data,
unsigned long num_data,
const mit_des_key_schedule ks1,
const mit_des_key_schedule ks2,
const mit_des_key_schedule ks3,
mit_des_cblock ivec)
{
unsigned DES_INT32 left, right;
const unsigned DES_INT32 *kp1, *kp2, *kp3;
const unsigned char *ip;
unsigned DES_INT32 ocipherl, ocipherr;
unsigned DES_INT32 cipherl, cipherr;
unsigned char *op;
struct iov_block_state input_pos, output_pos;
unsigned char iblock[MIT_DES_BLOCK_LENGTH];
unsigned char oblock[MIT_DES_BLOCK_LENGTH];
IOV_BLOCK_STATE_INIT(&input_pos);
IOV_BLOCK_STATE_INIT(&output_pos);
/*
* Get key pointer here. This won't need to be reinitialized
*/
kp1 = (const unsigned DES_INT32 *)ks1;
kp2 = (const unsigned DES_INT32 *)ks2;
kp3 = (const unsigned DES_INT32 *)ks3;
/*
* Decrypting is harder than encrypting because of
* the necessity of remembering a lot more things.
* Should think about this a little more...
*/
if (num_data == 0)
return;
/*
* Prime the old cipher with ivec.
*/
if (ivec != NULL)
ip = ivec;
else
ip = mit_des_zeroblock;
GET_HALF_BLOCK(ocipherl, ip);
GET_HALF_BLOCK(ocipherr, ip);
/*
* Now do this in earnest until we run out of length.
*/
for (;;) {
/*
* Read a block from the input into left and
* right. Save this cipher block for later.
*/
if (!krb5int_c_iov_get_block(iblock, MIT_DES_BLOCK_LENGTH, data, num_data, &input_pos))
break;
if (input_pos.iov_pos == num_data)
break;
ip = iblock;
op = oblock;
GET_HALF_BLOCK(left, ip);
GET_HALF_BLOCK(right, ip);
cipherl = left;
cipherr = right;
/*
* Decrypt this.
*/
DES_DO_DECRYPT(left, right, kp3);
DES_DO_ENCRYPT(left, right, kp2);
DES_DO_DECRYPT(left, right, kp1);
/*
* Xor with the old cipher to get plain
* text. Output 8 or less bytes of this.
*/
left ^= ocipherl;
right ^= ocipherr;
PUT_HALF_BLOCK(left, op);
PUT_HALF_BLOCK(right, op);
/*
* Save current cipher block here
*/
ocipherl = cipherl;
ocipherr = cipherr;
krb5int_c_iov_put_block(data, num_data, oblock, MIT_DES_BLOCK_LENGTH, &output_pos);
}
if (ivec != NULL) {
op = ivec;
PUT_HALF_BLOCK(ocipherl,op);
PUT_HALF_BLOCK(ocipherr, op);
}
}
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