mirror of
https://github.com/vanhoefm/fragattacks.git
synced 2024-11-26 17:28:29 -05:00
84 lines
1.8 KiB
C
84 lines
1.8 KiB
C
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/*
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* FIPS 186-2 PRF for libcrypto
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* Copyright (c) 2004-2005, Jouni Malinen <j@w1.fi>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Alternatively, this software may be distributed under the terms of BSD
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* license.
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*
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* See README and COPYING for more details.
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*/
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#include "includes.h"
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#include <openssl/sha.h>
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#include "common.h"
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#include "crypto.h"
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static void sha1_transform(u8 *state, const u8 data[64])
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{
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SHA_CTX context;
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os_memset(&context, 0, sizeof(context));
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os_memcpy(&context.h0, state, 5 * 4);
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SHA1_Transform(&context, data);
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os_memcpy(state, &context.h0, 5 * 4);
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}
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int fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen)
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{
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u8 xkey[64];
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u32 t[5], _t[5];
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int i, j, m, k;
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u8 *xpos = x;
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u32 carry;
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if (seed_len > sizeof(xkey))
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seed_len = sizeof(xkey);
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/* FIPS 186-2 + change notice 1 */
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os_memcpy(xkey, seed, seed_len);
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os_memset(xkey + seed_len, 0, 64 - seed_len);
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t[0] = 0x67452301;
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t[1] = 0xEFCDAB89;
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t[2] = 0x98BADCFE;
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t[3] = 0x10325476;
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t[4] = 0xC3D2E1F0;
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m = xlen / 40;
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for (j = 0; j < m; j++) {
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/* XSEED_j = 0 */
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for (i = 0; i < 2; i++) {
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/* XVAL = (XKEY + XSEED_j) mod 2^b */
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/* w_i = G(t, XVAL) */
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os_memcpy(_t, t, 20);
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sha1_transform((u8 *) _t, xkey);
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_t[0] = host_to_be32(_t[0]);
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_t[1] = host_to_be32(_t[1]);
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_t[2] = host_to_be32(_t[2]);
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_t[3] = host_to_be32(_t[3]);
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_t[4] = host_to_be32(_t[4]);
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os_memcpy(xpos, _t, 20);
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/* XKEY = (1 + XKEY + w_i) mod 2^b */
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carry = 1;
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for (k = 19; k >= 0; k--) {
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carry += xkey[k] + xpos[k];
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xkey[k] = carry & 0xff;
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carry >>= 8;
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}
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xpos += 20;
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}
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/* x_j = w_0|w_1 */
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}
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return 0;
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}
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