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crypto: add support for PBKDF2 algorithm

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The LUKS data format includes use of PBKDF2 (Password-Based
Key Derivation Function). The Nettle library can provide
an implementation of this, but we don't want code directly
depending on a specific crypto library backend. Introduce
a new include/crypto/pbkdf.h header which defines a QEMU
API for invoking PBKDK2. The initial implementations are
backed by nettle & gcrypt, which are commonly available
with distros shipping GNUTLS.

The test suite data is taken from the cryptsetup codebase
under the LGPLv2.1+ license. This merely aims to verify
that whatever backend we provide for this function in QEMU
will comply with the spec.

Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
This commit is contained in:
Daniel P. Berrange 2015-10-14 13:14:04 +01:00
parent b917da4cbd
commit 37788f253a
10 changed files with 853 additions and 0 deletions
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68
crypto/pbkdf-gcrypt.c Normal file
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/*
* QEMU Crypto PBKDF support (Password-Based Key Derivation Function)
*
* Copyright (c) 2015-2016 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
*/
#include "qemu/osdep.h"
#include "crypto/pbkdf.h"
#include "gcrypt.h"
bool qcrypto_pbkdf2_supports(QCryptoHashAlgorithm hash)
{
switch (hash) {
case QCRYPTO_HASH_ALG_MD5:
case QCRYPTO_HASH_ALG_SHA1:
case QCRYPTO_HASH_ALG_SHA256:
return true;
default:
return false;
}
}
int qcrypto_pbkdf2(QCryptoHashAlgorithm hash,
const uint8_t *key, size_t nkey,
const uint8_t *salt, size_t nsalt,
unsigned int iterations,
uint8_t *out, size_t nout,
Error **errp)
{
static const int hash_map[QCRYPTO_HASH_ALG__MAX] = {
[QCRYPTO_HASH_ALG_MD5] = GCRY_MD_MD5,
[QCRYPTO_HASH_ALG_SHA1] = GCRY_MD_SHA1,
[QCRYPTO_HASH_ALG_SHA256] = GCRY_MD_SHA256,
};
int ret;
if (hash >= G_N_ELEMENTS(hash_map) ||
hash_map[hash] == GCRY_MD_NONE) {
error_setg(errp, "Unexpected hash algorithm %d", hash);
return -1;
}
ret = gcry_kdf_derive(key, nkey, GCRY_KDF_PBKDF2,
hash_map[hash],
salt, nsalt, iterations,
nout, out);
if (ret != 0) {
error_setg(errp, "Cannot derive password: %s",
gcry_strerror(ret));
return -1;
}
return 0;
}