|
1 /*- |
|
2 * Copyright 2005,2007,2009 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 #include <sys/types.h> |
|
27 |
|
28 #include <stdint.h> |
|
29 #include <string.h> |
|
30 |
|
31 #include <sys/endian.h> |
|
32 |
|
33 #include "pbkdf2_sha256.h" |
|
34 |
|
35 static inline uint32_t |
|
36 be32dec(const void *pp) |
|
37 { |
|
38 const uint8_t *p = (uint8_t const *)pp; |
|
39 |
|
40 return ((uint32_t)(p[3]) + |
|
41 ((uint32_t)(p[2]) << 8) + |
|
42 ((uint32_t)(p[1]) << 16) + |
|
43 ((uint32_t)(p[0]) << 24)); |
|
44 } |
|
45 |
|
46 static inline void |
|
47 be32enc(void *pp, uint32_t x) |
|
48 { |
|
49 uint8_t * p = (uint8_t *)pp; |
|
50 |
|
51 p[3] = x & 0xff; |
|
52 p[2] = (x >> 8) & 0xff; |
|
53 p[1] = (x >> 16) & 0xff; |
|
54 p[0] = (x >> 24) & 0xff; |
|
55 } |
|
56 |
|
57 /* |
|
58 * Encode a length len/4 vector of (uint32_t) into a length len vector of |
|
59 * (unsigned char) in big-endian form. Assumes len is a multiple of 4. |
|
60 */ |
|
61 static void |
|
62 be32enc_vect(unsigned char *dst, const uint32_t *src, size_t len) |
|
63 { |
|
64 size_t i; |
|
65 |
|
66 for (i = 0; i < len / 4; i++) |
|
67 be32enc(dst + i * 4, src[i]); |
|
68 } |
|
69 |
|
70 /* |
|
71 * Decode a big-endian length len vector of (unsigned char) into a length |
|
72 * len/4 vector of (uint32_t). Assumes len is a multiple of 4. |
|
73 */ |
|
74 static void |
|
75 be32dec_vect(uint32_t *dst, const unsigned char *src, size_t len) |
|
76 { |
|
77 size_t i; |
|
78 |
|
79 for (i = 0; i < len / 4; i++) |
|
80 dst[i] = be32dec(src + i * 4); |
|
81 } |
|
82 |
|
83 /* Elementary functions used by SHA256 */ |
|
84 #define Ch(x, y, z) ((x & (y ^ z)) ^ z) |
|
85 #define Maj(x, y, z) ((x & (y | z)) | (y & z)) |
|
86 #define SHR(x, n) (x >> n) |
|
87 #define ROTR(x, n) ((x >> n) | (x << (32 - n))) |
|
88 #define S0(x) (ROTR(x, 2) ^ ROTR(x, 13) ^ ROTR(x, 22)) |
|
89 #define S1(x) (ROTR(x, 6) ^ ROTR(x, 11) ^ ROTR(x, 25)) |
|
90 #define s0(x) (ROTR(x, 7) ^ ROTR(x, 18) ^ SHR(x, 3)) |
|
91 #define s1(x) (ROTR(x, 17) ^ ROTR(x, 19) ^ SHR(x, 10)) |
|
92 |
|
93 /* SHA256 round function */ |
|
94 #define RND(a, b, c, d, e, f, g, h, k) \ |
|
95 t0 = h + S1(e) + Ch(e, f, g) + k; \ |
|
96 t1 = S0(a) + Maj(a, b, c); \ |
|
97 d += t0; \ |
|
98 h = t0 + t1; |
|
99 |
|
100 /* Adjusted round function for rotating state */ |
|
101 #define RNDr(S, W, i, k) \ |
|
102 RND(S[(64 - i) % 8], S[(65 - i) % 8], \ |
|
103 S[(66 - i) % 8], S[(67 - i) % 8], \ |
|
104 S[(68 - i) % 8], S[(69 - i) % 8], \ |
|
105 S[(70 - i) % 8], S[(71 - i) % 8], \ |
|
106 W[i] + k) |
|
107 |
|
108 /* |
|
109 * SHA256 block compression function. The 256-bit state is transformed via |
|
110 * the 512-bit input block to produce a new state. |
|
111 */ |
|
112 static void |
|
113 SHA256_Transform(uint32_t * state, const unsigned char block[64]) |
|
114 { |
|
115 uint32_t W[64]; |
|
116 uint32_t S[8]; |
|
117 uint32_t t0, t1; |
|
118 int i; |
|
119 |
|
120 /* 1. Prepare message schedule W. */ |
|
121 be32dec_vect(W, block, 64); |
|
122 for (i = 16; i < 64; i++) |
|
123 W[i] = s1(W[i - 2]) + W[i - 7] + s0(W[i - 15]) + W[i - 16]; |
|
124 |
|
125 /* 2. Initialize working variables. */ |
|
126 memcpy(S, state, 32); |
|
127 |
|
128 /* 3. Mix. */ |
|
129 RNDr(S, W, 0, 0x428a2f98); |
|
130 RNDr(S, W, 1, 0x71374491); |
|
131 RNDr(S, W, 2, 0xb5c0fbcf); |
|
132 RNDr(S, W, 3, 0xe9b5dba5); |
|
133 RNDr(S, W, 4, 0x3956c25b); |
|
134 RNDr(S, W, 5, 0x59f111f1); |
|
135 RNDr(S, W, 6, 0x923f82a4); |
|
136 RNDr(S, W, 7, 0xab1c5ed5); |
|
137 RNDr(S, W, 8, 0xd807aa98); |
|
138 RNDr(S, W, 9, 0x12835b01); |
|
139 RNDr(S, W, 10, 0x243185be); |
|
140 RNDr(S, W, 11, 0x550c7dc3); |
|
141 RNDr(S, W, 12, 0x72be5d74); |
|
142 RNDr(S, W, 13, 0x80deb1fe); |
|
143 RNDr(S, W, 14, 0x9bdc06a7); |
|
144 RNDr(S, W, 15, 0xc19bf174); |
|
145 RNDr(S, W, 16, 0xe49b69c1); |
|
146 RNDr(S, W, 17, 0xefbe4786); |
|
147 RNDr(S, W, 18, 0x0fc19dc6); |
|
148 RNDr(S, W, 19, 0x240ca1cc); |
|
149 RNDr(S, W, 20, 0x2de92c6f); |
|
150 RNDr(S, W, 21, 0x4a7484aa); |
|
151 RNDr(S, W, 22, 0x5cb0a9dc); |
|
152 RNDr(S, W, 23, 0x76f988da); |
|
153 RNDr(S, W, 24, 0x983e5152); |
|
154 RNDr(S, W, 25, 0xa831c66d); |
|
155 RNDr(S, W, 26, 0xb00327c8); |
|
156 RNDr(S, W, 27, 0xbf597fc7); |
|
157 RNDr(S, W, 28, 0xc6e00bf3); |
|
158 RNDr(S, W, 29, 0xd5a79147); |
|
159 RNDr(S, W, 30, 0x06ca6351); |
|
160 RNDr(S, W, 31, 0x14292967); |
|
161 RNDr(S, W, 32, 0x27b70a85); |
|
162 RNDr(S, W, 33, 0x2e1b2138); |
|
163 RNDr(S, W, 34, 0x4d2c6dfc); |
|
164 RNDr(S, W, 35, 0x53380d13); |
|
165 RNDr(S, W, 36, 0x650a7354); |
|
166 RNDr(S, W, 37, 0x766a0abb); |
|
167 RNDr(S, W, 38, 0x81c2c92e); |
|
168 RNDr(S, W, 39, 0x92722c85); |
|
169 RNDr(S, W, 40, 0xa2bfe8a1); |
|
170 RNDr(S, W, 41, 0xa81a664b); |
|
171 RNDr(S, W, 42, 0xc24b8b70); |
|
172 RNDr(S, W, 43, 0xc76c51a3); |
|
173 RNDr(S, W, 44, 0xd192e819); |
|
174 RNDr(S, W, 45, 0xd6990624); |
|
175 RNDr(S, W, 46, 0xf40e3585); |
|
176 RNDr(S, W, 47, 0x106aa070); |
|
177 RNDr(S, W, 48, 0x19a4c116); |
|
178 RNDr(S, W, 49, 0x1e376c08); |
|
179 RNDr(S, W, 50, 0x2748774c); |
|
180 RNDr(S, W, 51, 0x34b0bcb5); |
|
181 RNDr(S, W, 52, 0x391c0cb3); |
|
182 RNDr(S, W, 53, 0x4ed8aa4a); |
|
183 RNDr(S, W, 54, 0x5b9cca4f); |
|
184 RNDr(S, W, 55, 0x682e6ff3); |
|
185 RNDr(S, W, 56, 0x748f82ee); |
|
186 RNDr(S, W, 57, 0x78a5636f); |
|
187 RNDr(S, W, 58, 0x84c87814); |
|
188 RNDr(S, W, 59, 0x8cc70208); |
|
189 RNDr(S, W, 60, 0x90befffa); |
|
190 RNDr(S, W, 61, 0xa4506ceb); |
|
191 RNDr(S, W, 62, 0xbef9a3f7); |
|
192 RNDr(S, W, 63, 0xc67178f2); |
|
193 |
|
194 /* 4. Mix local working variables into global state. */ |
|
195 for (i = 0; i < 8; i++) |
|
196 state[i] += S[i]; |
|
197 |
|
198 /* Clean the stack. */ |
|
199 memset(W, 0, 256); |
|
200 memset(S, 0, 32); |
|
201 t0 = t1 = 0; |
|
202 } |
|
203 |
|
204 static unsigned char PAD[64] = { |
|
205 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
|
206 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
|
207 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
|
208 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 |
|
209 }; |
|
210 |
|
211 /* Add padding and terminating bit-count. */ |
|
212 static void |
|
213 SHA256_Pad(SHA256_CTX * ctx) |
|
214 { |
|
215 unsigned char len[8]; |
|
216 uint32_t r, plen; |
|
217 |
|
218 /* |
|
219 * Convert length to a vector of bytes -- we do this now rather |
|
220 * than later because the length will change after we pad. |
|
221 */ |
|
222 be32enc_vect(len, ctx->count, 8); |
|
223 |
|
224 /* Add 1--64 bytes so that the resulting length is 56 mod 64. */ |
|
225 r = (ctx->count[1] >> 3) & 0x3f; |
|
226 plen = (r < 56) ? (56 - r) : (120 - r); |
|
227 SHA256_Update(ctx, PAD, (size_t)plen); |
|
228 |
|
229 /* Add the terminating bit-count. */ |
|
230 SHA256_Update(ctx, len, 8); |
|
231 } |
|
232 |
|
233 /* SHA-256 initialization. Begins a SHA-256 operation. */ |
|
234 void |
|
235 SHA256_Init(SHA256_CTX * ctx) |
|
236 { |
|
237 |
|
238 /* Zero bits processed so far. */ |
|
239 ctx->count[0] = ctx->count[1] = 0; |
|
240 |
|
241 /* Magic initialization constants. */ |
|
242 ctx->state[0] = 0x6A09E667; |
|
243 ctx->state[1] = 0xBB67AE85; |
|
244 ctx->state[2] = 0x3C6EF372; |
|
245 ctx->state[3] = 0xA54FF53A; |
|
246 ctx->state[4] = 0x510E527F; |
|
247 ctx->state[5] = 0x9B05688C; |
|
248 ctx->state[6] = 0x1F83D9AB; |
|
249 ctx->state[7] = 0x5BE0CD19; |
|
250 } |
|
251 |
|
252 /* Add bytes into the hash. */ |
|
253 void |
|
254 SHA256_Update(SHA256_CTX * ctx, const void *in, size_t len) |
|
255 { |
|
256 uint32_t bitlen[2]; |
|
257 uint32_t r; |
|
258 const unsigned char *src = in; |
|
259 |
|
260 /* Number of bytes left in the buffer from previous updates. */ |
|
261 r = (ctx->count[1] >> 3) & 0x3f; |
|
262 |
|
263 /* Convert the length into a number of bits. */ |
|
264 bitlen[1] = ((uint32_t)len) << 3; |
|
265 bitlen[0] = (uint32_t)(len >> 29); |
|
266 |
|
267 /* Update number of bits. */ |
|
268 if ((ctx->count[1] += bitlen[1]) < bitlen[1]) |
|
269 ctx->count[0]++; |
|
270 ctx->count[0] += bitlen[0]; |
|
271 |
|
272 /* Handle the case where we don't need to perform any transforms. */ |
|
273 if (len < 64 - r) { |
|
274 memcpy(&ctx->buf[r], src, len); |
|
275 return; |
|
276 } |
|
277 |
|
278 /* Finish the current block. */ |
|
279 memcpy(&ctx->buf[r], src, 64 - r); |
|
280 SHA256_Transform(ctx->state, ctx->buf); |
|
281 src += 64 - r; |
|
282 len -= 64 - r; |
|
283 |
|
284 /* Perform complete blocks. */ |
|
285 while (len >= 64) { |
|
286 SHA256_Transform(ctx->state, src); |
|
287 src += 64; |
|
288 len -= 64; |
|
289 } |
|
290 |
|
291 /* Copy left over data into buffer. */ |
|
292 memcpy(ctx->buf, src, len); |
|
293 } |
|
294 |
|
295 /* |
|
296 * SHA-256 finalization. Pads the input data, exports the hash value, |
|
297 * and clears the context state. |
|
298 */ |
|
299 void |
|
300 SHA256_Final(unsigned char digest[32], SHA256_CTX * ctx) |
|
301 { |
|
302 |
|
303 /* Add padding. */ |
|
304 SHA256_Pad(ctx); |
|
305 |
|
306 /* Write the hash. */ |
|
307 be32enc_vect(digest, ctx->state, 32); |
|
308 |
|
309 /* Clear the context state. */ |
|
310 memset((void *)ctx, 0, sizeof(*ctx)); |
|
311 } |
|
312 |
|
313 /* Initialize an HMAC-SHA256 operation with the given key. */ |
|
314 void |
|
315 HMAC_SHA256_Init(HMAC_SHA256_CTX * ctx, const void * _K, size_t Klen) |
|
316 { |
|
317 unsigned char pad[64]; |
|
318 unsigned char khash[32]; |
|
319 const unsigned char * K = _K; |
|
320 size_t i; |
|
321 |
|
322 /* If Klen > 64, the key is really SHA256(K). */ |
|
323 if (Klen > 64) { |
|
324 SHA256_Init(&ctx->ictx); |
|
325 SHA256_Update(&ctx->ictx, K, Klen); |
|
326 SHA256_Final(khash, &ctx->ictx); |
|
327 K = khash; |
|
328 Klen = 32; |
|
329 } |
|
330 |
|
331 /* Inner SHA256 operation is SHA256(K xor [block of 0x36] || data). */ |
|
332 SHA256_Init(&ctx->ictx); |
|
333 memset(pad, 0x36, 64); |
|
334 for (i = 0; i < Klen; i++) |
|
335 pad[i] ^= K[i]; |
|
336 SHA256_Update(&ctx->ictx, pad, 64); |
|
337 |
|
338 /* Outer SHA256 operation is SHA256(K xor [block of 0x5c] || hash). */ |
|
339 SHA256_Init(&ctx->octx); |
|
340 memset(pad, 0x5c, 64); |
|
341 for (i = 0; i < Klen; i++) |
|
342 pad[i] ^= K[i]; |
|
343 SHA256_Update(&ctx->octx, pad, 64); |
|
344 |
|
345 /* Clean the stack. */ |
|
346 memset(khash, 0, 32); |
|
347 } |
|
348 |
|
349 /* Add bytes to the HMAC-SHA256 operation. */ |
|
350 void |
|
351 HMAC_SHA256_Update(HMAC_SHA256_CTX * ctx, const void *in, size_t len) |
|
352 { |
|
353 |
|
354 /* Feed data to the inner SHA256 operation. */ |
|
355 SHA256_Update(&ctx->ictx, in, len); |
|
356 } |
|
357 |
|
358 /* Finish an HMAC-SHA256 operation. */ |
|
359 void |
|
360 HMAC_SHA256_Final(unsigned char digest[32], HMAC_SHA256_CTX * ctx) |
|
361 { |
|
362 unsigned char ihash[32]; |
|
363 |
|
364 /* Finish the inner SHA256 operation. */ |
|
365 SHA256_Final(ihash, &ctx->ictx); |
|
366 |
|
367 /* Feed the inner hash to the outer SHA256 operation. */ |
|
368 SHA256_Update(&ctx->octx, ihash, 32); |
|
369 |
|
370 /* Finish the outer SHA256 operation. */ |
|
371 SHA256_Final(digest, &ctx->octx); |
|
372 |
|
373 /* Clean the stack. */ |
|
374 memset(ihash, 0, 32); |
|
375 } |
|
376 |
|
377 /** |
|
378 * PBKDF2_SHA256(passwd, passwdlen, salt, saltlen, c, buf, dkLen): |
|
379 * Compute PBKDF2(passwd, salt, c, dkLen) using HMAC-SHA256 as the PRF, and |
|
380 * write the output to buf. The value dkLen must be at most 32 * (2^32 - 1). |
|
381 */ |
|
382 void |
|
383 PBKDF2_SHA256(const uint8_t * passwd, size_t passwdlen, const uint8_t * salt, |
|
384 size_t saltlen, uint64_t c, uint8_t * buf, size_t dkLen) |
|
385 { |
|
386 HMAC_SHA256_CTX PShctx, hctx; |
|
387 size_t i; |
|
388 uint8_t ivec[4]; |
|
389 uint8_t U[32]; |
|
390 uint8_t T[32]; |
|
391 uint64_t j; |
|
392 int k; |
|
393 size_t clen; |
|
394 |
|
395 /* Compute HMAC state after processing P and S. */ |
|
396 HMAC_SHA256_Init(&PShctx, passwd, passwdlen); |
|
397 HMAC_SHA256_Update(&PShctx, salt, saltlen); |
|
398 |
|
399 /* Iterate through the blocks. */ |
|
400 for (i = 0; i * 32 < dkLen; i++) { |
|
401 /* Generate INT(i + 1). */ |
|
402 be32enc(ivec, (uint32_t)(i + 1)); |
|
403 |
|
404 /* Compute U_1 = PRF(P, S || INT(i)). */ |
|
405 memcpy(&hctx, &PShctx, sizeof(HMAC_SHA256_CTX)); |
|
406 HMAC_SHA256_Update(&hctx, ivec, 4); |
|
407 HMAC_SHA256_Final(U, &hctx); |
|
408 |
|
409 /* T_i = U_1 ... */ |
|
410 memcpy(T, U, 32); |
|
411 |
|
412 for (j = 2; j <= c; j++) { |
|
413 /* Compute U_j. */ |
|
414 HMAC_SHA256_Init(&hctx, passwd, passwdlen); |
|
415 HMAC_SHA256_Update(&hctx, U, 32); |
|
416 HMAC_SHA256_Final(U, &hctx); |
|
417 |
|
418 /* ... xor U_j ... */ |
|
419 for (k = 0; k < 32; k++) |
|
420 T[k] ^= U[k]; |
|
421 } |
|
422 |
|
423 /* Copy as many bytes as necessary into buf. */ |
|
424 clen = dkLen - i * 32; |
|
425 if (clen > 32) |
|
426 clen = 32; |
|
427 memcpy(&buf[i * 32], T, clen); |
|
428 } |
|
429 |
|
430 /* Clean PShctx, since we never called _Final on it. */ |
|
431 memset(&PShctx, 0, sizeof(HMAC_SHA256_CTX)); |
|
432 } |