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
27 #include <limits.h>
28 #include <stdint.h>
29 #include <stdlib.h>
30 #include <string.h>
31
32 #include <sys/types.h>
33
34 #include "core.h"
35 #include "crypto_auth_hmacsha256.h"
36 #include "crypto_pwhash_scryptsalsa208sha256.h"
37 #include "pbkdf2-sha256.h"
38 #include "private/common.h"
39 #include "utils.h"
40
41 /**
42 * PBKDF2_SHA256(passwd, passwdlen, salt, saltlen, c, buf, dkLen):
43 * Compute PBKDF2(passwd, salt, c, dkLen) using HMAC-SHA256 as the PRF, and
44 * write the output to buf. The value dkLen must be at most 32 * (2^32 - 1).
45 */
46 void
PBKDF2_SHA256(const uint8_t * passwd,size_t passwdlen,const uint8_t * salt,size_t saltlen,uint64_t c,uint8_t * buf,size_t dkLen)47 PBKDF2_SHA256(const uint8_t *passwd, size_t passwdlen, const uint8_t *salt,
48 size_t saltlen, uint64_t c, uint8_t *buf, size_t dkLen)
49 {
50 crypto_auth_hmacsha256_state PShctx, hctx;
51 size_t i;
52 uint8_t ivec[4];
53 uint8_t U[32];
54 uint8_t T[32];
55 uint64_t j;
56 int k;
57 size_t clen;
58
59 #if SIZE_MAX > 0x1fffffffe0ULL
60 COMPILER_ASSERT(crypto_pwhash_scryptsalsa208sha256_BYTES_MAX
61 <= 0x1fffffffe0ULL);
62 if (dkLen > 0x1fffffffe0ULL) {
63 sodium_misuse(); /* LCOV_EXCL_LINE */
64 }
65 #endif
66 crypto_auth_hmacsha256_init(&PShctx, passwd, passwdlen);
67 crypto_auth_hmacsha256_update(&PShctx, salt, saltlen);
68
69 for (i = 0; i * 32 < dkLen; i++) {
70 STORE32_BE(ivec, (uint32_t)(i + 1));
71 memcpy(&hctx, &PShctx, sizeof(crypto_auth_hmacsha256_state));
72 crypto_auth_hmacsha256_update(&hctx, ivec, 4);
73 crypto_auth_hmacsha256_final(&hctx, U);
74
75 memcpy(T, U, 32);
76 /* LCOV_EXCL_START */
77 for (j = 2; j <= c; j++) {
78 crypto_auth_hmacsha256_init(&hctx, passwd, passwdlen);
79 crypto_auth_hmacsha256_update(&hctx, U, 32);
80 crypto_auth_hmacsha256_final(&hctx, U);
81
82 for (k = 0; k < 32; k++) {
83 T[k] ^= U[k];
84 }
85 }
86 /* LCOV_EXCL_STOP */
87
88 clen = dkLen - i * 32;
89 if (clen > 32) {
90 clen = 32;
91 }
92 memcpy(&buf[i * 32], T, clen);
93 }
94 sodium_memzero((void *) &PShctx, sizeof PShctx);
95 }
96