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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 | #include "sha256.h" | |
37 | #include "sysendian.h" | |
38 | ||
39 | #include "crypto_scrypt.h" | |
40 | ||
41 | static void blkcpy(uint8_t *, uint8_t *, size_t); | |
42 | static void blkxor(uint8_t *, uint8_t *, size_t); | |
43 | static void salsa20_8(uint8_t[64]); | |
44 | static void blockmix_salsa8(uint8_t *, uint8_t *, size_t); | |
45 | static uint64_t integerify(uint8_t *, size_t); | |
46 | static void smix(uint8_t *, size_t, uint64_t, uint8_t *, uint8_t *); | |
47 | ||
48 | static void | |
49 | blkcpy(uint8_t * dest, uint8_t * src, size_t len) | |
50 | { | |
51 | size_t i; | |
52 | ||
53 | for (i = 0; i < len; i++) | |
54 | dest[i] = src[i]; | |
55 | } | |
56 | ||
57 | static void | |
58 | blkxor(uint8_t * dest, uint8_t * src, size_t len) | |
59 | { | |
60 | size_t i; | |
61 | ||
62 | for (i = 0; i < len; i++) | |
63 | dest[i] ^= src[i]; | |
64 | } | |
65 | ||
66 | /** | |
67 | * salsa20_8(B): | |
68 | * Apply the salsa20/8 core to the provided block. | |
69 | */ | |
70 | static void | |
71 | salsa20_8(uint8_t B[64]) | |
72 | { | |
73 | uint32_t B32[16]; | |
74 | uint32_t x[16]; | |
75 | size_t i; | |
76 | ||
77 | /* Convert little-endian values in. */ | |
78 | for (i = 0; i < 16; i++) | |
79 | B32[i] = le32dec(&B[i * 4]); | |
80 | ||
81 | /* Compute x = doubleround^4(B32). */ | |
82 | for (i = 0; i < 16; i++) | |
83 | x[i] = B32[i]; | |
84 | for (i = 0; i < 8; i += 2) { | |
85 | #define R(a,b) (((a) << (b)) | ((a) >> (32 - (b)))) | |
86 | /* Operate on columns. */ | |
87 | x[ 4] ^= R(x[ 0]+x[12], 7); x[ 8] ^= R(x[ 4]+x[ 0], 9); | |
88 | x[12] ^= R(x[ 8]+x[ 4],13); x[ 0] ^= R(x[12]+x[ 8],18); | |
89 | ||
90 | x[ 9] ^= R(x[ 5]+x[ 1], 7); x[13] ^= R(x[ 9]+x[ 5], 9); | |
91 | x[ 1] ^= R(x[13]+x[ 9],13); x[ 5] ^= R(x[ 1]+x[13],18); | |
92 | ||
93 | x[14] ^= R(x[10]+x[ 6], 7); x[ 2] ^= R(x[14]+x[10], 9); | |
94 | x[ 6] ^= R(x[ 2]+x[14],13); x[10] ^= R(x[ 6]+x[ 2],18); | |
95 | ||
96 | x[ 3] ^= R(x[15]+x[11], 7); x[ 7] ^= R(x[ 3]+x[15], 9); | |
97 | x[11] ^= R(x[ 7]+x[ 3],13); x[15] ^= R(x[11]+x[ 7],18); | |
98 | ||
99 | /* Operate on rows. */ | |
100 | x[ 1] ^= R(x[ 0]+x[ 3], 7); x[ 2] ^= R(x[ 1]+x[ 0], 9); | |
101 | x[ 3] ^= R(x[ 2]+x[ 1],13); x[ 0] ^= R(x[ 3]+x[ 2],18); | |
102 | ||
103 | x[ 6] ^= R(x[ 5]+x[ 4], 7); x[ 7] ^= R(x[ 6]+x[ 5], 9); | |
104 | x[ 4] ^= R(x[ 7]+x[ 6],13); x[ 5] ^= R(x[ 4]+x[ 7],18); | |
105 | ||
106 | x[11] ^= R(x[10]+x[ 9], 7); x[ 8] ^= R(x[11]+x[10], 9); | |
107 | x[ 9] ^= R(x[ 8]+x[11],13); x[10] ^= R(x[ 9]+x[ 8],18); | |
108 | ||
109 | x[12] ^= R(x[15]+x[14], 7); x[13] ^= R(x[12]+x[15], 9); | |
110 | x[14] ^= R(x[13]+x[12],13); x[15] ^= R(x[14]+x[13],18); | |
111 | #undef R | |
112 | } | |
113 | ||
114 | /* Compute B32 = B32 + x. */ | |
115 | for (i = 0; i < 16; i++) | |
116 | B32[i] += x[i]; | |
117 | ||
118 | /* Convert little-endian values out. */ | |
119 | for (i = 0; i < 16; i++) | |
120 | le32enc(&B[4 * i], B32[i]); | |
121 | } | |
122 | ||
123 | /** | |
124 | * blockmix_salsa8(B, Y, r): | |
125 | * Compute B = BlockMix_{salsa20/8, r}(B). The input B must be 128r bytes in | |
126 | * length; the temporary space Y must also be the same size. | |
127 | */ | |
128 | static void | |
129 | blockmix_salsa8(uint8_t * B, uint8_t * Y, size_t r) | |
130 | { | |
131 | uint8_t X[64]; | |
132 | size_t i; | |
133 | ||
134 | /* 1: X <-- B_{2r - 1} */ | |
135 | blkcpy(X, &B[(2 * r - 1) * 64], 64); | |
136 | ||
137 | /* 2: for i = 0 to 2r - 1 do */ | |
138 | for (i = 0; i < 2 * r; i++) { | |
139 | /* 3: X <-- H(X \xor B_i) */ | |
140 | blkxor(X, &B[i * 64], 64); | |
141 | salsa20_8(X); | |
142 | ||
143 | /* 4: Y_i <-- X */ | |
144 | blkcpy(&Y[i * 64], X, 64); | |
145 | } | |
146 | ||
147 | /* 6: B' <-- (Y_0, Y_2 ... Y_{2r-2}, Y_1, Y_3 ... Y_{2r-1}) */ | |
148 | for (i = 0; i < r; i++) | |
149 | blkcpy(&B[i * 64], &Y[(i * 2) * 64], 64); | |
150 | for (i = 0; i < r; i++) | |
151 | blkcpy(&B[(i + r) * 64], &Y[(i * 2 + 1) * 64], 64); | |
152 | } | |
153 | ||
154 | /** | |
155 | * integerify(B, r): | |
156 | * Return the result of parsing B_{2r-1} as a little-endian integer. | |
157 | */ | |
158 | static uint64_t | |
159 | integerify(uint8_t * B, size_t r) | |
160 | { | |
161 | uint8_t * X = &B[(2 * r - 1) * 64]; | |
162 | ||
163 | return (le64dec(X)); | |
164 | } | |
165 | ||
166 | /** | |
167 | * smix(B, r, N, V, XY): | |
168 | * Compute B = SMix_r(B, N). The input B must be 128r bytes in length; the | |
169 | * temporary storage V must be 128rN bytes in length; the temporary storage | |
170 | * XY must be 256r bytes in length. The value N must be a power of 2. | |
171 | */ | |
172 | static void | |
173 | smix(uint8_t * B, size_t r, uint64_t N, uint8_t * V, uint8_t * XY) | |
174 | { | |
175 | uint8_t * X = XY; | |
176 | uint8_t * Y = &XY[128 * r]; | |
177 | uint64_t i; | |
178 | uint64_t j; | |
179 | ||
180 | /* 1: X <-- B */ | |
181 | blkcpy(X, B, 128 * r); | |
182 | ||
183 | /* 2: for i = 0 to N - 1 do */ | |
184 | for (i = 0; i < N; i++) { | |
185 | /* 3: V_i <-- X */ | |
186 | blkcpy(&V[i * (128 * r)], X, 128 * r); | |
187 | ||
188 | /* 4: X <-- H(X) */ | |
189 | blockmix_salsa8(X, Y, r); | |
190 | } | |
191 | ||
192 | /* 6: for i = 0 to N - 1 do */ | |
193 | for (i = 0; i < N; i++) { | |
194 | /* 7: j <-- Integerify(X) mod N */ | |
195 | j = integerify(X, r) & (N - 1); | |
196 | ||
197 | /* 8: X <-- H(X \xor V_j) */ | |
198 | blkxor(X, &V[j * (128 * r)], 128 * r); | |
199 | blockmix_salsa8(X, Y, r); | |
200 | } | |
201 | ||
202 | /* 10: B' <-- X */ | |
203 | blkcpy(B, X, 128 * r); | |
204 | } | |
205 | ||
206 | /** | |
207 | * crypto_scrypt(passwd, passwdlen, salt, saltlen, N, r, p, buf, buflen): | |
208 | * Compute scrypt(passwd[0 .. passwdlen - 1], salt[0 .. saltlen - 1], N, r, | |
209 | * p, buflen) and write the result into buf. The parameters r, p, and buflen | |
210 | * must satisfy r * p < 2^30 and buflen <= (2^32 - 1) * 32. The parameter N | |
211 | * must be a power of 2. | |
212 | * | |
213 | * Return 0 on success; or -1 on error. | |
214 | */ | |
215 | int | |
216 | crypto_scrypt(const uint8_t * passwd, size_t passwdlen, | |
217 | const uint8_t * salt, size_t saltlen, uint64_t N, uint32_t _r, uint32_t _p, | |
218 | uint8_t * buf, size_t buflen) | |
219 | { | |
220 | uint8_t * B; | |
221 | uint8_t * V; | |
222 | uint8_t * XY; | |
223 | size_t r = _r, p = _p; | |
224 | uint32_t i; | |
225 | ||
226 | /* Sanity-check parameters. */ | |
227 | #if SIZE_MAX > UINT32_MAX | |
228 | if (buflen > (((uint64_t)(1) << 32) - 1) * 32) { | |
229 | errno = EFBIG; | |
230 | goto err0; | |
231 | } | |
232 | #endif | |
233 | if ((uint64_t)(r) * (uint64_t)(p) >= (1 << 30)) { | |
234 | errno = EFBIG; | |
235 | goto err0; | |
236 | } | |
237 | if (((N & (N - 1)) != 0) || (N == 0)) { | |
238 | errno = EINVAL; | |
239 | goto err0; | |
240 | } | |
241 | if ((r > SIZE_MAX / 128 / p) || | |
242 | #if SIZE_MAX / 256 <= UINT32_MAX | |
243 | (r > SIZE_MAX / 256) || | |
244 | #endif | |
245 | (N > SIZE_MAX / 128 / r)) { | |
246 | errno = ENOMEM; | |
247 | goto err0; | |
248 | } | |
249 | ||
250 | /* Allocate memory. */ | |
251 | if ((B = malloc(128 * r * p)) == NULL) | |
252 | goto err0; | |
253 | if ((XY = malloc(256 * r)) == NULL) | |
254 | goto err1; | |
255 | if ((V = malloc(128 * r * N)) == NULL) | |
256 | goto err2; | |
257 | ||
258 | /* 1: (B_0 ... B_{p-1}) <-- PBKDF2(P, S, 1, p * MFLen) */ | |
259 | PBKDF2_SHA256(passwd, passwdlen, salt, saltlen, 1, B, p * 128 * r); | |
260 | ||
261 | /* 2: for i = 0 to p - 1 do */ | |
262 | for (i = 0; i < p; i++) { | |
263 | /* 3: B_i <-- MF(B_i, N) */ | |
264 | smix(&B[i * 128 * r], r, N, V, XY); | |
265 | } | |
266 | ||
267 | /* 5: DK <-- PBKDF2(P, B, 1, dkLen) */ | |
268 | PBKDF2_SHA256(passwd, passwdlen, B, p * 128 * r, 1, buf, buflen); | |
269 | ||
270 | /* Free memory. */ | |
271 | free(V); | |
272 | free(XY); | |
273 | free(B); | |
274 | ||
275 | /* Success! */ | |
276 | return (0); | |
277 | ||
278 | err2: | |
279 | free(XY); | |
280 | err1: | |
281 | free(B); | |
282 | err0: | |
283 | /* Failure! */ | |
284 | return (-1); | |
285 | } |