pkcs5_pbkdf2.c
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/* $OpenBSD: pkcs5_pbkdf2.c,v 1.4 2013/06/03 21:07:02 tedu Exp $ */
/*-
* Copyright (c) 2008 Damien Bergamini <damien.bergamini@free.fr>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/param.h>
#include <string.h>
#include <limits.h>
#include <stdlib.h>
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//#include <util.h>
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#include "sha1.h"
/*
* Password-Based Key Derivation Function 2 (PKCS #5 v2.0).
* Code based on IEEE Std 802.11-2007, Annex H.4.2.
*/
int
pkcs5_pbkdf2(const char *pass, size_t pass_len, const uint8_t *salt, size_t salt_len,
uint8_t *key, size_t key_len, unsigned int rounds)
{
uint8_t *asalt, obuf[SHA1_DIGEST_LENGTH];
uint8_t d1[SHA1_DIGEST_LENGTH], d2[SHA1_DIGEST_LENGTH];
unsigned int i, j;
unsigned int count;
size_t r;
if (rounds < 1 || key_len == 0)
return -1;
if (salt_len == 0 || salt_len > SIZE_MAX - 4)
return -1;
if ((asalt = malloc(salt_len + 4)) == NULL)
return -1;
memcpy(asalt, salt, salt_len);
for (count = 1; key_len > 0; count++) {
asalt[salt_len + 0] = (count >> 24) & 0xff;
asalt[salt_len + 1] = (count >> 16) & 0xff;
asalt[salt_len + 2] = (count >> 8) & 0xff;
asalt[salt_len + 3] = count & 0xff;
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SHA1Hmac((const uint8_t *) pass, pass_len, asalt, salt_len + 4, d1);
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memcpy(obuf, d1, sizeof(obuf));
for (i = 1; i < rounds; i++) {
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SHA1Hmac((const uint8_t *) pass, pass_len, d1, sizeof(d1), d2);
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memcpy(d1, d2, sizeof(d1));
for (j = 0; j < sizeof(obuf); j++)
obuf[j] ^= d1[j];
}
r = MIN(key_len, SHA1_DIGEST_LENGTH);
memcpy(key, obuf, r);
key += r;
key_len -= r;
};
bzero(asalt, salt_len + 4);
free(asalt);
bzero(d1, sizeof(d1));
bzero(d2, sizeof(d2));
bzero(obuf, sizeof(obuf));
return 0;
}