1/*
2 * FIPS 186-2 PRF for libcrypto
3 * Copyright (c) 2004-2005, 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 <openssl/sha.h>
11
12#include "common.h"
13#include "crypto.h"
14
15
16static void sha1_transform(u32 *state, const u8 data[64])
17{
18	SHA_CTX context;
19	os_memset(&context, 0, sizeof(context));
20#if defined(OPENSSL_IS_BORINGSSL) && !defined(ANDROID)
21	context.h[0] = state[0];
22	context.h[1] = state[1];
23	context.h[2] = state[2];
24	context.h[3] = state[3];
25	context.h[4] = state[4];
26	SHA1_Transform(&context, data);
27	state[0] = context.h[0];
28	state[1] = context.h[1];
29	state[2] = context.h[2];
30	state[3] = context.h[3];
31	state[4] = context.h[4];
32#else
33	context.h0 = state[0];
34	context.h1 = state[1];
35	context.h2 = state[2];
36	context.h3 = state[3];
37	context.h4 = state[4];
38	SHA1_Transform(&context, data);
39	state[0] = context.h0;
40	state[1] = context.h1;
41	state[2] = context.h2;
42	state[3] = context.h3;
43	state[4] = context.h4;
44#endif
45}
46
47
48int fips186_2_prf(const u8 *seed, size_t seed_len, u8 *x, size_t xlen)
49{
50	u8 xkey[64];
51	u32 t[5], _t[5];
52	int i, j, m, k;
53	u8 *xpos = x;
54	u32 carry;
55
56	if (seed_len < sizeof(xkey))
57		os_memset(xkey + seed_len, 0, sizeof(xkey) - seed_len);
58	else
59		seed_len = sizeof(xkey);
60
61	/* FIPS 186-2 + change notice 1 */
62
63	os_memcpy(xkey, seed, seed_len);
64	t[0] = 0x67452301;
65	t[1] = 0xEFCDAB89;
66	t[2] = 0x98BADCFE;
67	t[3] = 0x10325476;
68	t[4] = 0xC3D2E1F0;
69
70	m = xlen / 40;
71	for (j = 0; j < m; j++) {
72		/* XSEED_j = 0 */
73		for (i = 0; i < 2; i++) {
74			/* XVAL = (XKEY + XSEED_j) mod 2^b */
75
76			/* w_i = G(t, XVAL) */
77			os_memcpy(_t, t, 20);
78			sha1_transform(_t, xkey);
79			WPA_PUT_BE32(xpos, _t[0]);
80			WPA_PUT_BE32(xpos + 4, _t[1]);
81			WPA_PUT_BE32(xpos + 8, _t[2]);
82			WPA_PUT_BE32(xpos + 12, _t[3]);
83			WPA_PUT_BE32(xpos + 16, _t[4]);
84
85			/* XKEY = (1 + XKEY + w_i) mod 2^b */
86			carry = 1;
87			for (k = 19; k >= 0; k--) {
88				carry += xkey[k] + xpos[k];
89				xkey[k] = carry & 0xff;
90				carry >>= 8;
91			}
92
93			xpos += 20;
94		}
95		/* x_j = w_0|w_1 */
96	}
97
98	return 0;
99}
100