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