hostap/src/crypto/fips_prf_openssl.c

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