86 lines
2.2 KiB
C
86 lines
2.2 KiB
C
#include <stdio.h>
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#include <string.h>
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#include <stddef.h>
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#include <sys/types.h>
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#include <freeswan.h>
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#include "constants.h"
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#include "defs.h"
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#include "log.h"
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#include "libtwofish/twofish_cbc.h"
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#include "alg_info.h"
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#include "ike_alg.h"
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#define TWOFISH_CBC_BLOCK_SIZE (128/BITS_PER_BYTE)
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#define TWOFISH_KEY_MIN_LEN 128
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#define TWOFISH_KEY_DEF_LEN 128
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#define TWOFISH_KEY_MAX_LEN 256
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static void
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do_twofish(u_int8_t *buf, size_t buf_size, u_int8_t *key, size_t key_size, u_int8_t *iv, bool enc)
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{
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twofish_context twofish_ctx;
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char iv_bak[TWOFISH_CBC_BLOCK_SIZE];
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char *new_iv = NULL; /* logic will avoid copy to NULL */
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twofish_set_key(&twofish_ctx, key, key_size);
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/*
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* my TWOFISH cbc does not touch passed IV (optimization for
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* ESP handling), so I must "emulate" des-like IV
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* crunching
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*/
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if (!enc)
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memcpy(new_iv=iv_bak,
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(char*) buf + buf_size-TWOFISH_CBC_BLOCK_SIZE,
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TWOFISH_CBC_BLOCK_SIZE);
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twofish_cbc_encrypt(&twofish_ctx, buf, buf, buf_size, iv, enc);
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if (enc)
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new_iv = (char*) buf + buf_size-TWOFISH_CBC_BLOCK_SIZE;
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memcpy(iv, new_iv, TWOFISH_CBC_BLOCK_SIZE);
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}
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struct encrypt_desc encrypt_desc_twofish =
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{
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algo_type: IKE_ALG_ENCRYPT,
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algo_id: OAKLEY_TWOFISH_CBC,
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algo_next: NULL,
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enc_ctxsize: sizeof(twofish_context),
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enc_blocksize: TWOFISH_CBC_BLOCK_SIZE,
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keydeflen: TWOFISH_KEY_MIN_LEN,
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keyminlen: TWOFISH_KEY_DEF_LEN,
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keymaxlen: TWOFISH_KEY_MAX_LEN,
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do_crypt: do_twofish,
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};
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struct encrypt_desc encrypt_desc_twofish_ssh =
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{
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algo_type: IKE_ALG_ENCRYPT,
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algo_id: OAKLEY_TWOFISH_CBC_SSH,
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algo_next: NULL,
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enc_ctxsize: sizeof(twofish_context),
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enc_blocksize: TWOFISH_CBC_BLOCK_SIZE,
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keydeflen: TWOFISH_KEY_MIN_LEN,
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keyminlen: TWOFISH_KEY_DEF_LEN,
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keymaxlen: TWOFISH_KEY_MAX_LEN,
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do_crypt: do_twofish,
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};
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int ike_alg_twofish_init(void);
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int
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ike_alg_twofish_init(void)
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{
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int ret = ike_alg_register_enc(&encrypt_desc_twofish);
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if (ike_alg_register_enc(&encrypt_desc_twofish_ssh) < 0)
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plog("ike_alg_twofish_init(): Experimental OAKLEY_TWOFISH_CBC_SSH activation failed");
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return ret;
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}
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/*
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IKE_ALG_INIT_NAME: ike_alg_twofish_init
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*/
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