1/*
2 * FIPS 186-2 PRF for libcrypto
3 * Copyright (c) 2004-2017, Jouni Malinen <j@w1.fi>
4 *
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
7 */
8
9#include "includes.h"
10#include <wolfssl/options.h>
11#include <wolfssl/wolfcrypt/sha.h>
12
13#include "common.h"
14#include "crypto.h"
15
16
17static void sha1_transform(u32 *state, const u8 data[64])
18{
19	wc_Sha sha;
20
21	os_memset(&sha, 0, sizeof(sha));
22	sha.digest[0] = state[0];
23	sha.digest[1] = state[1];
24	sha.digest[2] = state[2];
25	sha.digest[3] = state[3];
26	sha.digest[4] = state[4];
27	wc_ShaUpdate(&sha, data, 64);
28	state[0] = sha.digest[0];
29	state[1] = sha.digest[1];
30	state[2] = sha.digest[2];
31	state[3] = sha.digest[3];
32	state[4] = sha.digest[4];
33}
34
35
36int fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen)
37{
38	u8 xkey[64];
39	u32 t[5], _t[5];
40	int i, j, m, k;
41	u8 *xpos = x;
42	u32 carry;
43
44	if (seed_len < sizeof(xkey))
45		os_memset(xkey + seed_len, 0, sizeof(xkey) - seed_len);
46	else
47		seed_len = sizeof(xkey);
48
49	/* FIPS 186-2 + change notice 1 */
50
51	os_memcpy(xkey, seed, seed_len);
52	t[0] = 0x67452301;
53	t[1] = 0xEFCDAB89;
54	t[2] = 0x98BADCFE;
55	t[3] = 0x10325476;
56	t[4] = 0xC3D2E1F0;
57
58	m = xlen / 40;
59	for (j = 0; j < m; j++) {
60		/* XSEED_j = 0 */
61		for (i = 0; i < 2; i++) {
62			/* XVAL = (XKEY + XSEED_j) mod 2^b */
63
64			/* w_i = G(t, XVAL) */
65			os_memcpy(_t, t, 20);
66			sha1_transform(_t, xkey);
67			WPA_PUT_BE32(xpos, _t[0]);
68			WPA_PUT_BE32(xpos + 4, _t[1]);
69			WPA_PUT_BE32(xpos + 8, _t[2]);
70			WPA_PUT_BE32(xpos + 12, _t[3]);
71			WPA_PUT_BE32(xpos + 16, _t[4]);
72
73			/* XKEY = (1 + XKEY + w_i) mod 2^b */
74			carry = 1;
75			for (k = 19; k >= 0; k--) {
76				carry += xkey[k] + xpos[k];
77				xkey[k] = carry & 0xff;
78				carry >>= 8;
79			}
80
81			xpos += 20;
82		}
83		/* x_j = w_0|w_1 */
84	}
85
86	return 0;
87}
88