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/*-
* 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/malloc.h>
#include <sys/systm.h>
#include <geom/geom.h>
#else
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <errno.h>
#endif
#include <geom/eli/g_eli.h>
/*
* Verify if the given 'key' is correct.
* Return 1 if it is correct and 0 otherwise.
*/
static int
g_eli_mkey_verify(const unsigned char *mkey, const unsigned char *key)
{
const unsigned char *odhmac; /* On-disk HMAC. */
unsigned char chmac[SHA512_MDLEN]; /* Calculated HMAC. */
unsigned char hmkey[SHA512_MDLEN]; /* Key for HMAC. */
/*
* The key for HMAC calculations is: hmkey = HMAC_SHA512(Derived-Key, 0)
*/
g_eli_crypto_hmac(key, G_ELI_USERKEYLEN, "\x00", 1, hmkey, 0);
odhmac = mkey + G_ELI_DATAIVKEYLEN;
/* Calculate HMAC from Data-Key and IV-Key. */
g_eli_crypto_hmac(hmkey, sizeof(hmkey), mkey, G_ELI_DATAIVKEYLEN,
chmac, 0);
bzero(hmkey, sizeof(hmkey));
/*
* Compare calculated HMAC with HMAC from metadata.
* If two HMACs are equal, 'key' is correct.
*/
return (!bcmp(odhmac, chmac, SHA512_MDLEN));
}
/*
* Calculate HMAC from Data-Key and IV-Key.
*/
void
g_eli_mkey_hmac(unsigned char *mkey, const unsigned char *key)
{
unsigned char hmkey[SHA512_MDLEN]; /* Key for HMAC. */
unsigned char *odhmac; /* On-disk HMAC. */
/*
* The key for HMAC calculations is: hmkey = HMAC_SHA512(Derived-Key, 0)
*/
g_eli_crypto_hmac(key, G_ELI_USERKEYLEN, "\x00", 1, hmkey, 0);
odhmac = mkey + G_ELI_DATAIVKEYLEN;
/* Calculate HMAC from Data-Key and IV-Key. */
g_eli_crypto_hmac(hmkey, sizeof(hmkey), mkey, G_ELI_DATAIVKEYLEN,
odhmac, 0);
bzero(hmkey, sizeof(hmkey));
}
/*
* Find and decrypt Master Key encrypted with 'key'.
* Return decrypted Master Key number in 'nkeyp' if not NULL.
* Return 0 on success, > 0 on failure, -1 on bad key.
*/
int
g_eli_mkey_decrypt(const struct g_eli_metadata *md, const unsigned char *key,
unsigned char *mkey, unsigned *nkeyp)
{
unsigned char tmpmkey[G_ELI_MKEYLEN];
unsigned char enckey[SHA512_MDLEN]; /* Key for encryption. */
const unsigned char *mmkey;
int bit, error, nkey;
if (nkeyp != NULL)
*nkeyp = -1;
/*
* The key for encryption is: enckey = HMAC_SHA512(Derived-Key, 1)
*/
g_eli_crypto_hmac(key, G_ELI_USERKEYLEN, "\x01", 1, enckey, 0);
mmkey = md->md_mkeys;
nkey = 0;
for (nkey = 0; nkey < G_ELI_MAXMKEYS; nkey++, mmkey += G_ELI_MKEYLEN) {
bit = (1 << nkey);
if (!(md->md_keys & bit))
continue;
bcopy(mmkey, tmpmkey, G_ELI_MKEYLEN);
error = g_eli_crypto_decrypt(md->md_ealgo, tmpmkey,
G_ELI_MKEYLEN, enckey, md->md_keylen);
if (error != 0) {
bzero(tmpmkey, sizeof(tmpmkey));
bzero(enckey, sizeof(enckey));
return (error);
}
if (g_eli_mkey_verify(tmpmkey, key)) {
bcopy(tmpmkey, mkey, G_ELI_DATAIVKEYLEN);
bzero(tmpmkey, sizeof(tmpmkey));
bzero(enckey, sizeof(enckey));
if (nkeyp != NULL)
*nkeyp = nkey;
return (0);
}
}
bzero(enckey, sizeof(enckey));
bzero(tmpmkey, sizeof(tmpmkey));
return (-1);
}
/*
* Encrypt the Master-Key and calculate HMAC to be able to verify it in the
* future.
*/
int
g_eli_mkey_encrypt(unsigned algo, const unsigned char *key, unsigned keylen,
unsigned char *mkey)
{
unsigned char enckey[SHA512_MDLEN]; /* Key for encryption. */
int error;
/*
* To calculate HMAC, the whole key (G_ELI_USERKEYLEN bytes long) will
* be used.
*/
g_eli_mkey_hmac(mkey, key);
/*
* The key for encryption is: enckey = HMAC_SHA512(Derived-Key, 1)
*/
g_eli_crypto_hmac(key, G_ELI_USERKEYLEN, "\x01", 1, enckey, 0);
/*
* Encrypt the Master-Key and HMAC() result with the given key (this
* time only 'keylen' bits from the key are used).
*/
error = g_eli_crypto_encrypt(algo, mkey, G_ELI_MKEYLEN, enckey, keylen);
bzero(enckey, sizeof(enckey));
return (error);
}
#ifdef _KERNEL
/*
* When doing encryption only, copy IV key and encryption key.
* When doing encryption and authentication, copy IV key, generate encryption
* key and generate authentication key.
*/
void
g_eli_mkey_propagate(struct g_eli_softc *sc, const unsigned char *mkey)
{
/* Remember the Master Key. */
bcopy(mkey, sc->sc_mkey, sizeof(sc->sc_mkey));
bcopy(mkey, sc->sc_ivkey, sizeof(sc->sc_ivkey));
mkey += sizeof(sc->sc_ivkey);
if (!(sc->sc_flags & G_ELI_FLAG_AUTH)) {
bcopy(mkey, sc->sc_ekey, sizeof(sc->sc_ekey));
} else {
/*
* The encryption key is: ekey = HMAC_SHA512(Master-Key, 0x10)
* The authentication key is: akey = HMAC_SHA512(Master-Key, 0x11)
*/
g_eli_crypto_hmac(mkey, G_ELI_MAXKEYLEN, "\x10", 1, sc->sc_ekey, 0);
g_eli_crypto_hmac(mkey, G_ELI_MAXKEYLEN, "\x11", 1, sc->sc_akey, 0);
}
}
#endif
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