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/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* lib/crypto/enc_provider/camellia.c - Camellia enc provider definition */
/*
* Copyright (C) 2009, 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>
#ifdef CAMELLIA
/*
* Private per-key data to cache after first generation. We don't want to mess
* with the imported Cemallia implementation too much, so we'll just use two
* copies of its context, one for encryption and one for decryption, and use
* the #rounds field as a flag for whether we've initialized each half.
*/
struct camellia_key_info_cache {
camellia_ctx enc_ctx, dec_ctx;
};
#define CACHE(X) ((struct camellia_key_info_cache *)((X)->cache))
static inline void
enc(unsigned char *out, const unsigned char *in, camellia_ctx *ctx)
{
if (camellia_enc_blk(in, out, ctx) != camellia_good)
abort();
}
static inline void
dec(unsigned char *out, const unsigned char *in, camellia_ctx *ctx)
{
if (camellia_dec_blk(in, out, ctx) != camellia_good)
abort();
}
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];
const unsigned char *inptr = &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);
}
}
static krb5_error_code
krb5int_camellia_encrypt(krb5_key key, const krb5_data *ivec,
krb5_crypto_iov *data, size_t num_data)
{
unsigned char tmp[BLOCK_SIZE], tmp2[BLOCK_SIZE];
int nblocks = 0, blockno;
size_t input_length, i;
struct iov_block_state input_pos, output_pos;
if (key->cache == NULL) {
key->cache = malloc(sizeof(struct camellia_key_info_cache));
if (key->cache == NULL)
return ENOMEM;
CACHE(key)->enc_ctx.keybitlen = CACHE(key)->dec_ctx.keybitlen = 0;
}
if (CACHE(key)->enc_ctx.keybitlen == 0) {
if (camellia_enc_key(key->keyblock.contents, key->keyblock.length,
&CACHE(key)->enc_ctx) != camellia_good)
abort();
}
if (ivec != NULL)
memcpy(tmp, ivec->data, BLOCK_SIZE);
else
memset(tmp, 0, BLOCK_SIZE);
for (i = 0, input_length = 0; i < num_data; i++) {
krb5_crypto_iov *iov = &data[i];
if (ENCRYPT_IOV(iov))
input_length += iov->data.length;
}
IOV_BLOCK_STATE_INIT(&input_pos);
IOV_BLOCK_STATE_INIT(&output_pos);
nblocks = (input_length + BLOCK_SIZE - 1) / BLOCK_SIZE;
if (nblocks == 1) {
krb5int_c_iov_get_block(tmp, BLOCK_SIZE, data, num_data, &input_pos);
enc(tmp2, tmp, &CACHE(key)->enc_ctx);
krb5int_c_iov_put_block(data, num_data, tmp2, BLOCK_SIZE, &output_pos);
} else if (nblocks > 1) {
unsigned char blockN2[BLOCK_SIZE]; /* second last */
unsigned char blockN1[BLOCK_SIZE]; /* last block */
for (blockno = 0; blockno < nblocks - 2; blockno++) {
unsigned char blockN[BLOCK_SIZE], *block;
krb5int_c_iov_get_block_nocopy(blockN, BLOCK_SIZE,
data, num_data, &input_pos, &block);
xorblock(tmp, block);
enc(block, tmp, &CACHE(key)->enc_ctx);
krb5int_c_iov_put_block_nocopy(data, num_data, blockN, BLOCK_SIZE,
&output_pos, block);
/* Set up for next block. */
memcpy(tmp, block, BLOCK_SIZE);
}
/* Do final CTS step for last two blocks (the second of which
may or may not be incomplete). */
/* First, get the last two blocks */
memset(blockN1, 0, sizeof(blockN1)); /* pad last block with zeros */
krb5int_c_iov_get_block(blockN2, BLOCK_SIZE, data, num_data,
&input_pos);
krb5int_c_iov_get_block(blockN1, BLOCK_SIZE, data, num_data,
&input_pos);
/* Encrypt second last block */
xorblock(tmp, blockN2);
enc(tmp2, tmp, &CACHE(key)->enc_ctx);
memcpy(blockN2, tmp2, BLOCK_SIZE); /* blockN2 now contains first block */
memcpy(tmp, tmp2, BLOCK_SIZE);
/* Encrypt last block */
xorblock(tmp, blockN1);
enc(tmp2, tmp, &CACHE(key)->enc_ctx);
memcpy(blockN1, tmp2, BLOCK_SIZE);
/* Put the last two blocks back into the iovec (reverse order) */
krb5int_c_iov_put_block(data, num_data, blockN1, BLOCK_SIZE,
&output_pos);
krb5int_c_iov_put_block(data, num_data, blockN2, BLOCK_SIZE,
&output_pos);
if (ivec != NULL)
memcpy(ivec->data, blockN1, BLOCK_SIZE);
}
return 0;
}
static krb5_error_code
krb5int_camellia_decrypt(krb5_key key, const krb5_data *ivec,
krb5_crypto_iov *data, size_t num_data)
{
unsigned char tmp[BLOCK_SIZE], tmp2[BLOCK_SIZE], tmp3[BLOCK_SIZE];
int nblocks = 0, blockno;
unsigned int i;
size_t input_length;
struct iov_block_state input_pos, output_pos;
if (key->cache == NULL) {
key->cache = malloc(sizeof(struct camellia_key_info_cache));
if (key->cache == NULL)
return ENOMEM;
CACHE(key)->enc_ctx.keybitlen = CACHE(key)->dec_ctx.keybitlen = 0;
}
if (CACHE(key)->dec_ctx.keybitlen == 0) {
if (camellia_dec_key(key->keyblock.contents, key->keyblock.length,
&CACHE(key)->dec_ctx) != camellia_good)
abort();
}
if (ivec != NULL)
memcpy(tmp, ivec->data, BLOCK_SIZE);
else
memset(tmp, 0, BLOCK_SIZE);
for (i = 0, input_length = 0; i < num_data; i++) {
krb5_crypto_iov *iov = &data[i];
if (ENCRYPT_IOV(iov))
input_length += iov->data.length;
}
IOV_BLOCK_STATE_INIT(&input_pos);
IOV_BLOCK_STATE_INIT(&output_pos);
nblocks = (input_length + BLOCK_SIZE - 1) / BLOCK_SIZE;
if (nblocks == 1) {
krb5int_c_iov_get_block(tmp, BLOCK_SIZE, data, num_data, &input_pos);
dec(tmp2, tmp, &CACHE(key)->dec_ctx);
krb5int_c_iov_put_block(data, num_data, tmp2, BLOCK_SIZE, &output_pos);
} else if (nblocks > 1) {
unsigned char blockN2[BLOCK_SIZE]; /* second last */
unsigned char blockN1[BLOCK_SIZE]; /* last block */
for (blockno = 0; blockno < nblocks - 2; blockno++) {
unsigned char blockN[BLOCK_SIZE], *block;
krb5int_c_iov_get_block_nocopy(blockN, BLOCK_SIZE,
data, num_data, &input_pos, &block);
memcpy(tmp2, block, BLOCK_SIZE);
dec(block, block, &CACHE(key)->dec_ctx);
xorblock(block, tmp);
memcpy(tmp, tmp2, BLOCK_SIZE);
krb5int_c_iov_put_block_nocopy(data, num_data, blockN, BLOCK_SIZE,
&output_pos, block);
}
/* Do last two blocks, the second of which (next-to-last block
of plaintext) may be incomplete. */
/* First, get the last two encrypted blocks */
memset(blockN1, 0, sizeof(blockN1)); /* pad last block with zeros */
krb5int_c_iov_get_block(blockN2, BLOCK_SIZE, data, num_data,
&input_pos);
krb5int_c_iov_get_block(blockN1, BLOCK_SIZE, data, num_data,
&input_pos);
if (ivec != NULL)
memcpy(ivec->data, blockN2, BLOCK_SIZE);
/* Decrypt second last block */
dec(tmp2, blockN2, &CACHE(key)->dec_ctx);
/* Set tmp2 to last (possibly partial) plaintext block, and
save it. */
xorblock(tmp2, blockN1);
memcpy(blockN2, tmp2, BLOCK_SIZE);
/* Maybe keep the trailing part, and copy in the last
ciphertext block. */
input_length %= BLOCK_SIZE;
memcpy(tmp2, blockN1, input_length ? input_length : BLOCK_SIZE);
dec(tmp3, tmp2, &CACHE(key)->dec_ctx);
xorblock(tmp3, tmp);
memcpy(blockN1, tmp3, BLOCK_SIZE);
/* Put the last two blocks back into the iovec */
krb5int_c_iov_put_block(data, num_data, blockN1, BLOCK_SIZE,
&output_pos);
krb5int_c_iov_put_block(data, num_data, blockN2, BLOCK_SIZE,
&output_pos);
}
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);
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
camellia_init_state(const krb5_keyblock *key, krb5_keyusage usage,
krb5_data *state)
{
state->length = 16;
state->data = malloc(16);
if (state->data == NULL)
return ENOMEM;
memset(state->data, 0, state->length);
return 0;
}
const struct krb5_enc_provider krb5int_enc_camellia128 = {
16,
16, 16,
krb5int_camellia_encrypt,
krb5int_camellia_decrypt,
krb5int_camellia_cbc_mac,
krb5int_camellia_make_key,
camellia_init_state,
krb5int_default_free_state,
};
const struct krb5_enc_provider krb5int_enc_camellia256 = {
16,
32, 32,
krb5int_camellia_encrypt,
krb5int_camellia_decrypt,
krb5int_camellia_cbc_mac,
krb5int_camellia_make_key,
camellia_init_state,
krb5int_default_free_state
};
#else /* CAMELLIA */
/* These won't be used, but are still in the export table. */
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)
{
return EINVAL;
}
const struct krb5_enc_provider krb5int_enc_camellia128 = {
};
#endif /* CAMELLIA */
|