1/*-
2 * Copyright 2009 Colin Percival
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * This file was originally written by Colin Percival as part of the Tarsnap
27 * online backup system.
28 */
29#include "scrypt_platform.h"
30
31#include <errno.h>
32#include <stdint.h>
33#include <stdlib.h>
34#include <string.h>
35
36#ifdef USE_OPENSSL_PBKDF2
37#include <openssl/evp.h>
38#else
39#include "sha256.h"
40#endif
41#include "sysendian.h"
42
43#include "crypto_scrypt.h"
44
45static void blkcpy(uint8_t *, uint8_t *, size_t);
46static void blkxor(uint8_t *, uint8_t *, size_t);
47static void salsa20_8(uint8_t[64]);
48static void blockmix_salsa8(uint8_t *, uint8_t *, size_t);
49static uint64_t integerify(uint8_t *, size_t);
50static void smix(uint8_t *, size_t, uint64_t, uint8_t *, uint8_t *);
51
52static void
53blkcpy(uint8_t * dest, uint8_t * src, size_t len)
54{
55	size_t i;
56
57	for (i = 0; i < len; i++)
58		dest[i] = src[i];
59}
60
61static void
62blkxor(uint8_t * dest, uint8_t * src, size_t len)
63{
64	size_t i;
65
66	for (i = 0; i < len; i++)
67		dest[i] ^= src[i];
68}
69
70/**
71 * salsa20_8(B):
72 * Apply the salsa20/8 core to the provided block.
73 */
74static void
75salsa20_8(uint8_t B[64])
76{
77	uint32_t B32[16];
78	uint32_t x[16];
79	size_t i;
80
81	/* Convert little-endian values in. */
82	for (i = 0; i < 16; i++)
83		B32[i] = le32dec(&B[i * 4]);
84
85	/* Compute x = doubleround^4(B32). */
86	for (i = 0; i < 16; i++)
87		x[i] = B32[i];
88	for (i = 0; i < 8; i += 2) {
89#define R(a,b) (((a) << (b)) | ((a) >> (32 - (b))))
90		/* Operate on columns. */
91		x[ 4] ^= R(x[ 0]+x[12], 7);  x[ 8] ^= R(x[ 4]+x[ 0], 9);
92		x[12] ^= R(x[ 8]+x[ 4],13);  x[ 0] ^= R(x[12]+x[ 8],18);
93
94		x[ 9] ^= R(x[ 5]+x[ 1], 7);  x[13] ^= R(x[ 9]+x[ 5], 9);
95		x[ 1] ^= R(x[13]+x[ 9],13);  x[ 5] ^= R(x[ 1]+x[13],18);
96
97		x[14] ^= R(x[10]+x[ 6], 7);  x[ 2] ^= R(x[14]+x[10], 9);
98		x[ 6] ^= R(x[ 2]+x[14],13);  x[10] ^= R(x[ 6]+x[ 2],18);
99
100		x[ 3] ^= R(x[15]+x[11], 7);  x[ 7] ^= R(x[ 3]+x[15], 9);
101		x[11] ^= R(x[ 7]+x[ 3],13);  x[15] ^= R(x[11]+x[ 7],18);
102
103		/* Operate on rows. */
104		x[ 1] ^= R(x[ 0]+x[ 3], 7);  x[ 2] ^= R(x[ 1]+x[ 0], 9);
105		x[ 3] ^= R(x[ 2]+x[ 1],13);  x[ 0] ^= R(x[ 3]+x[ 2],18);
106
107		x[ 6] ^= R(x[ 5]+x[ 4], 7);  x[ 7] ^= R(x[ 6]+x[ 5], 9);
108		x[ 4] ^= R(x[ 7]+x[ 6],13);  x[ 5] ^= R(x[ 4]+x[ 7],18);
109
110		x[11] ^= R(x[10]+x[ 9], 7);  x[ 8] ^= R(x[11]+x[10], 9);
111		x[ 9] ^= R(x[ 8]+x[11],13);  x[10] ^= R(x[ 9]+x[ 8],18);
112
113		x[12] ^= R(x[15]+x[14], 7);  x[13] ^= R(x[12]+x[15], 9);
114		x[14] ^= R(x[13]+x[12],13);  x[15] ^= R(x[14]+x[13],18);
115#undef R
116	}
117
118	/* Compute B32 = B32 + x. */
119	for (i = 0; i < 16; i++)
120		B32[i] += x[i];
121
122	/* Convert little-endian values out. */
123	for (i = 0; i < 16; i++)
124		le32enc(&B[4 * i], B32[i]);
125}
126
127/**
128 * blockmix_salsa8(B, Y, r):
129 * Compute B = BlockMix_{salsa20/8, r}(B).  The input B must be 128r bytes in
130 * length; the temporary space Y must also be the same size.
131 */
132static void
133blockmix_salsa8(uint8_t * B, uint8_t * Y, size_t r)
134{
135	uint8_t X[64];
136	size_t i;
137
138	/* 1: X <-- B_{2r - 1} */
139	blkcpy(X, &B[(2 * r - 1) * 64], 64);
140
141	/* 2: for i = 0 to 2r - 1 do */
142	for (i = 0; i < 2 * r; i++) {
143		/* 3: X <-- H(X \xor B_i) */
144		blkxor(X, &B[i * 64], 64);
145		salsa20_8(X);
146
147		/* 4: Y_i <-- X */
148		blkcpy(&Y[i * 64], X, 64);
149	}
150
151	/* 6: B' <-- (Y_0, Y_2 ... Y_{2r-2}, Y_1, Y_3 ... Y_{2r-1}) */
152	for (i = 0; i < r; i++)
153		blkcpy(&B[i * 64], &Y[(i * 2) * 64], 64);
154	for (i = 0; i < r; i++)
155		blkcpy(&B[(i + r) * 64], &Y[(i * 2 + 1) * 64], 64);
156}
157
158/**
159 * integerify(B, r):
160 * Return the result of parsing B_{2r-1} as a little-endian integer.
161 */
162static uint64_t
163integerify(uint8_t * B, size_t r)
164{
165	uint8_t * X = &B[(2 * r - 1) * 64];
166
167	return (le64dec(X));
168}
169
170/**
171 * smix(B, r, N, V, XY):
172 * Compute B = SMix_r(B, N).  The input B must be 128r bytes in length; the
173 * temporary storage V must be 128rN bytes in length; the temporary storage
174 * XY must be 256r bytes in length.  The value N must be a power of 2.
175 */
176static void
177smix(uint8_t * B, size_t r, uint64_t N, uint8_t * V, uint8_t * XY)
178{
179	uint8_t * X = XY;
180	uint8_t * Y = &XY[128 * r];
181	uint64_t i;
182	uint64_t j;
183
184	/* 1: X <-- B */
185	blkcpy(X, B, 128 * r);
186
187	/* 2: for i = 0 to N - 1 do */
188	for (i = 0; i < N; i++) {
189		/* 3: V_i <-- X */
190		blkcpy(&V[i * (128 * r)], X, 128 * r);
191
192		/* 4: X <-- H(X) */
193		blockmix_salsa8(X, Y, r);
194	}
195
196	/* 6: for i = 0 to N - 1 do */
197	for (i = 0; i < N; i++) {
198		/* 7: j <-- Integerify(X) mod N */
199		j = integerify(X, r) & (N - 1);
200
201		/* 8: X <-- H(X \xor V_j) */
202		blkxor(X, &V[j * (128 * r)], 128 * r);
203		blockmix_salsa8(X, Y, r);
204	}
205
206	/* 10: B' <-- X */
207	blkcpy(B, X, 128 * r);
208}
209
210/**
211 * crypto_scrypt(passwd, passwdlen, salt, saltlen, N, r, p, buf, buflen):
212 * Compute scrypt(passwd[0 .. passwdlen - 1], salt[0 .. saltlen - 1], N, r,
213 * p, buflen) and write the result into buf.  The parameters r, p, and buflen
214 * must satisfy r * p < 2^30 and buflen <= (2^32 - 1) * 32.  The parameter N
215 * must be a power of 2.
216 *
217 * Return 0 on success; or -1 on error.
218 */
219int
220crypto_scrypt(const uint8_t * passwd, size_t passwdlen,
221    const uint8_t * salt, size_t saltlen, uint64_t N, uint32_t r, uint32_t p,
222    uint8_t * buf, size_t buflen)
223{
224	uint8_t * B;
225	uint8_t * V;
226	uint8_t * XY;
227	uint32_t i;
228
229	/* Sanity-check parameters. */
230#if SIZE_MAX > UINT32_MAX
231	if (buflen > (((uint64_t)(1) << 32) - 1) * 32) {
232		errno = EFBIG;
233		goto err0;
234	}
235#endif
236	if ((uint64_t)(r) * (uint64_t)(p) >= (1 << 30)) {
237		errno = EFBIG;
238		goto err0;
239	}
240	if (((N & (N - 1)) != 0) || (N == 0)) {
241		errno = EINVAL;
242		goto err0;
243	}
244	if ((r > SIZE_MAX / 128 / p) ||
245#if SIZE_MAX / 256 <= UINT32_MAX
246	    (r > SIZE_MAX / 256) ||
247#endif
248	    (N > SIZE_MAX / 128 / r)) {
249		errno = ENOMEM;
250		goto err0;
251	}
252
253	/* Allocate memory. */
254	if ((B = malloc(128 * r * p)) == NULL)
255		goto err0;
256	if ((XY = malloc(256 * r)) == NULL)
257		goto err1;
258	if ((V = malloc(128 * r * N)) == NULL)
259		goto err2;
260
261	/* 1: (B_0 ... B_{p-1}) <-- PBKDF2(P, S, 1, p * MFLen) */
262#ifdef USE_OPENSSL_PBKDF2
263	PKCS5_PBKDF2_HMAC((const char *)passwd, passwdlen, salt, saltlen, 1, EVP_sha256(), p * 128 * r, B);
264#else
265	PBKDF2_SHA256(passwd, passwdlen, salt, saltlen, 1, B, p * 128 * r);
266#endif
267
268	/* 2: for i = 0 to p - 1 do */
269	for (i = 0; i < p; i++) {
270		/* 3: B_i <-- MF(B_i, N) */
271		smix(&B[i * 128 * r], r, N, V, XY);
272	}
273
274	/* 5: DK <-- PBKDF2(P, B, 1, dkLen) */
275#ifdef USE_OPENSSL_PBKDF2
276	PKCS5_PBKDF2_HMAC((const char *)passwd, passwdlen, B, p * 128 * r, 1, EVP_sha256(), buflen, buf);
277#else
278	PBKDF2_SHA256(passwd, passwdlen, B, p * 128 * r, 1, buf, buflen);
279#endif
280
281	/* Free memory. */
282	free(V);
283	free(XY);
284	free(B);
285
286	/* Success! */
287	return (0);
288
289err2:
290	free(XY);
291err1:
292	free(B);
293err0:
294	/* Failure! */
295	return (-1);
296}
297