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
45 static void blkcpy(uint8_t *, uint8_t *, size_t);
46 static void blkxor(uint8_t *, uint8_t *, size_t);
47 static void salsa20_8(uint8_t[64]);
48 static void blockmix_salsa8(uint8_t *, uint8_t *, size_t);
49 static uint64_t integerify(uint8_t *, size_t);
50 static void smix(uint8_t *, size_t, uint64_t, uint8_t *, uint8_t *);
51
52 static void
blkcpy(uint8_t * dest,uint8_t * src,size_t len)53 blkcpy(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
61 static void
blkxor(uint8_t * dest,uint8_t * src,size_t len)62 blkxor(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 */
74 static void
salsa20_8(uint8_t B[64])75 salsa20_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 */
132 static void
blockmix_salsa8(uint8_t * B,uint8_t * Y,size_t r)133 blockmix_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 */
162 static uint64_t
integerify(uint8_t * B,size_t r)163 integerify(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 */
176 static void
smix(uint8_t * B,size_t r,uint64_t N,uint8_t * V,uint8_t * XY)177 smix(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 */
219 int
crypto_scrypt(const uint8_t * passwd,size_t passwdlen,const uint8_t * salt,size_t saltlen,uint64_t N,uint32_t r,uint32_t p,uint8_t * buf,size_t buflen)220 crypto_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
289 err2:
290 free(XY);
291 err1:
292 free(B);
293 err0:
294 /* Failure! */
295 return (-1);
296 }
297