freebsd-dev/sys/geom/eli/pkcs5v2.c
2006-02-01 12:06:01 +00:00

124 lines
3.5 KiB
C

/*-
* Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#ifdef _KERNEL
#include <sys/systm.h>
#include <sys/kernel.h>
#else
#include <sys/resource.h>
#include <stdint.h>
#include <strings.h>
#endif
#include <geom/eli/g_eli.h>
#include <geom/eli/pkcs5v2.h>
static __inline void
xor(uint8_t *dst, const uint8_t *src, size_t size)
{
for (; size > 0; size--)
*dst++ ^= *src++;
}
void
pkcs5v2_genkey(uint8_t *key, unsigned keylen, const uint8_t *salt,
size_t saltsize, const char *passphrase, u_int iterations)
{
uint8_t md[SHA512_MDLEN], saltcount[saltsize + sizeof(uint32_t)];
uint8_t *counter, *keyp;
u_int i, bsize, passlen;
uint32_t count;
passlen = strlen(passphrase);
bzero(key, keylen);
bcopy(salt, saltcount, saltsize);
counter = saltcount + saltsize;
keyp = key;
for (count = 1; keylen > 0; count++, keylen -= bsize, keyp += bsize) {
bsize = MIN(keylen, sizeof(md));
counter[0] = (count >> 24) & 0xff;
counter[1] = (count >> 16) & 0xff;
counter[2] = (count >> 8) & 0xff;
counter[3] = count & 0xff;
g_eli_crypto_hmac(passphrase, passlen, saltcount,
sizeof(saltcount), md, 0);
xor(keyp, md, bsize);
for(i = 1; i < iterations; i++) {
g_eli_crypto_hmac(passphrase, passlen, md, sizeof(md),
md, 0);
xor(keyp, md, bsize);
}
}
}
#ifndef _KERNEL
/*
* Return the number of microseconds needed for 'interations' iterations.
*/
static int
pkcs5v2_probe(int iterations)
{
uint8_t key[G_ELI_USERKEYLEN], salt[G_ELI_SALTLEN];
uint8_t passphrase[] = "passphrase";
struct rusage start, end;
int usecs;
getrusage(RUSAGE_SELF, &start);
pkcs5v2_genkey(key, sizeof(key), salt, sizeof(salt), passphrase,
iterations);
getrusage(RUSAGE_SELF, &end);
usecs = end.ru_utime.tv_sec - start.ru_utime.tv_sec;
usecs *= 1000000;
usecs += end.ru_utime.tv_usec - start.ru_utime.tv_usec;
return (usecs);
}
/*
* Return the number of iterations which takes 'usecs' microseconds.
*/
int
pkcs5v2_calculate(int usecs)
{
int iterations, v;
for (iterations = 1; ; iterations <<= 1) {
v = pkcs5v2_probe(iterations);
if (v > 2000000)
break;
}
return (((intmax_t)iterations * (intmax_t)usecs) / v);
}
#endif /* !_KERNEL */