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/*
* lib/crypto/builtin/enc_provider/camellia_ctr.c
*
* Copyright (C) 2003, 2007-2010 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.
*/
#include "k5-int.h"
#include "enc_provider.h"
#include "camellia.h"
#include <aead.h>
#include <rand2key.h>
static void
xorblock(unsigned char *out, const unsigned char *in)
{
int z;
for (z = 0; z < BLOCK_SIZE/4; z++) {
unsigned char *outptr = &out[z*4];
unsigned char *inptr = (unsigned char *)&in[z*4];
/*
* Use unaligned accesses. On x86, this will probably still be faster
* than multiple byte accesses for unaligned data, and for aligned data
* should be far better. (One test indicated about 2.4% faster
* encryption for 1024-byte messages.)
*
* If some other CPU has really slow unaligned-word or byte accesses,
* perhaps this function (or the load/store helpers?) should test for
* alignment first.
*
* If byte accesses are faster than unaligned words, we may need to
* conditionalize on CPU type, as that may be hard to determine
* automatically.
*/
store_32_n (load_32_n(outptr) ^ load_32_n(inptr), outptr);
}
}
/* Get the current counter block number from the IV */
static inline void getctrblockno(krb5_ui_8 *pblockno,
const unsigned char ctr[BLOCK_SIZE])
{
*pblockno = load_64_be(&ctr[BLOCK_SIZE - 8]);
}
/* Store the current counter block number in the IV */
static inline void putctrblockno(krb5_ui_8 blockno,
unsigned char ctr[BLOCK_SIZE])
{
store_64_be(blockno, &ctr[BLOCK_SIZE - 8]);
}
/*
* ivec must be a correctly formatted counter block per SP800-38C A.3
*/
static krb5_error_code
krb5int_camellia_encrypt_ctr(krb5_key key,
const krb5_data *ivec,
krb5_crypto_iov *data,
size_t num_data)
{
camellia_ctx ctx;
unsigned char ctr[BLOCK_SIZE];
krb5_ui_8 blockno;
struct iov_block_state input_pos, output_pos;
if (camellia_enc_key(key->keyblock.contents,
key->keyblock.length, &ctx) != camellia_good)
abort();
IOV_BLOCK_STATE_INIT(&input_pos);
IOV_BLOCK_STATE_INIT(&output_pos);
/* Don't encrypt the header (B0), and use zero instead of IOV padding */
input_pos.ignore_header = output_pos.ignore_header = 1;
input_pos.pad_to_boundary = output_pos.pad_to_boundary = 1;
if (ivec == NULL)
return EINVAL;
if (ivec->length != BLOCK_SIZE)
return KRB5_BAD_MSIZE;
memcpy(ctr, ivec->data, BLOCK_SIZE);
getctrblockno(&blockno, ctr);
for (;;) {
unsigned char storage[BLOCK_SIZE], *block;
unsigned char ectr[BLOCK_SIZE];
if (!krb5int_c_iov_get_block_nocopy(storage, BLOCK_SIZE,
data, num_data, &input_pos, &block))
break;
if (camellia_enc_blk(ctr, ectr, &ctx) != camellia_good)
abort();
xorblock(block, ectr);
krb5int_c_iov_put_block_nocopy(data, num_data, storage, BLOCK_SIZE,
&output_pos, block);
putctrblockno(++blockno, ctr);
}
if (ivec != NULL)
memcpy(ivec->data, ctr, sizeof(ctr));
return 0;
}
krb5_error_code
krb5int_camellia_cbc_mac(krb5_key key,
const krb5_crypto_iov *data,
size_t num_data,
const krb5_data *iv,
krb5_data *output)
{
camellia_ctx ctx;
unsigned char blockY[BLOCK_SIZE];
struct iov_block_state iov_state;
if (output->length < BLOCK_SIZE)
return KRB5_BAD_MSIZE;
if (camellia_enc_key(key->keyblock.contents,
key->keyblock.length, &ctx) != camellia_good)
abort();
if (iv != NULL)
memcpy(blockY, iv->data, BLOCK_SIZE);
else
memset(blockY, 0, BLOCK_SIZE);
IOV_BLOCK_STATE_INIT(&iov_state);
/*
* The CCM header may not fit in a block, because it includes a variable
* length encoding of the associated data length. This encoding plus the
* associated data itself is padded to the block size.
*/
iov_state.include_sign_only = 1;
iov_state.pad_to_boundary = 1;
for (;;) {
unsigned char blockB[BLOCK_SIZE];
if (!krb5int_c_iov_get_block(blockB, BLOCK_SIZE, data, num_data, &iov_state))
break;
xorblock(blockB, blockY);
if (camellia_enc_blk(blockB, blockY, &ctx) != camellia_good)
abort();
}
output->length = BLOCK_SIZE;
memcpy(output->data, blockY, BLOCK_SIZE);
return 0;
}
static krb5_error_code
krb5int_camellia_init_state_ctr (const krb5_keyblock *key, krb5_keyusage usage,
krb5_data *state)
{
return alloc_data(state, 16);
}
const struct krb5_enc_provider krb5int_enc_camellia128_ctr = {
16,
16, 16,
krb5int_camellia_encrypt_ctr,
krb5int_camellia_encrypt_ctr,
krb5int_camellia_cbc_mac,
krb5int_camellia_make_key,
krb5int_camellia_init_state_ctr,
krb5int_default_free_state,
NULL
};
const struct krb5_enc_provider krb5int_enc_camellia256_ctr = {
16,
32, 32,
krb5int_camellia_encrypt_ctr,
krb5int_camellia_encrypt_ctr,
krb5int_camellia_cbc_mac,
krb5int_camellia_make_key,
krb5int_camellia_init_state_ctr,
krb5int_default_free_state,
NULL
};
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