qemu/block/crypto.h
Maxim Levitsky bbfdae91fb block/crypto: implement the encryption key management
This implements the encryption key management using the generic code in
qcrypto layer and exposes it to the user via qemu-img

This code adds another 'write_func' because the initialization
write_func works directly on the underlying file, and amend
works on instance of luks device.

This commit also adds a 'hack/workaround' I and Kevin Wolf (thanks)
made to make the driver both support write sharing (to avoid breaking the users),
and be safe against concurrent  metadata update (the keyslots)

Eventually the write sharing for luks driver will be deprecated
and removed together with this hack.

The hack is that we ask (as a format driver) for BLK_PERM_CONSISTENT_READ
and then when we want to update the keys, we unshare that permission.
So if someone else has the image open, even readonly, encryption
key update will fail gracefully.

Also thanks to Daniel Berrange for the idea of
unsharing read, rather that write permission which allows
to avoid cases when the other user had opened the image read-only.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200608094030.670121-8-mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
2020-07-06 08:49:28 +02:00

135 lines
5.7 KiB
C

/*
* QEMU block full disk encryption
*
* Copyright (c) 2015-2017 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/>.
*
*/
#ifndef BLOCK_CRYPTO_H
#define BLOCK_CRYPTO_H
#define BLOCK_CRYPTO_OPT_DEF_KEY_SECRET(prefix, helpstr) \
{ \
.name = prefix BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET, \
.type = QEMU_OPT_STRING, \
.help = helpstr, \
}
#define BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET "key-secret"
#define BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET(prefix) \
BLOCK_CRYPTO_OPT_DEF_KEY_SECRET(prefix, \
"ID of the secret that provides the AES encryption key")
#define BLOCK_CRYPTO_OPT_LUKS_KEY_SECRET "key-secret"
#define BLOCK_CRYPTO_OPT_LUKS_CIPHER_ALG "cipher-alg"
#define BLOCK_CRYPTO_OPT_LUKS_CIPHER_MODE "cipher-mode"
#define BLOCK_CRYPTO_OPT_LUKS_IVGEN_ALG "ivgen-alg"
#define BLOCK_CRYPTO_OPT_LUKS_IVGEN_HASH_ALG "ivgen-hash-alg"
#define BLOCK_CRYPTO_OPT_LUKS_HASH_ALG "hash-alg"
#define BLOCK_CRYPTO_OPT_LUKS_ITER_TIME "iter-time"
#define BLOCK_CRYPTO_OPT_LUKS_KEYSLOT "keyslot"
#define BLOCK_CRYPTO_OPT_LUKS_STATE "state"
#define BLOCK_CRYPTO_OPT_LUKS_OLD_SECRET "old-secret"
#define BLOCK_CRYPTO_OPT_LUKS_NEW_SECRET "new-secret"
#define BLOCK_CRYPTO_OPT_DEF_LUKS_KEY_SECRET(prefix) \
BLOCK_CRYPTO_OPT_DEF_KEY_SECRET(prefix, \
"ID of the secret that provides the keyslot passphrase")
#define BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG(prefix) \
{ \
.name = prefix BLOCK_CRYPTO_OPT_LUKS_CIPHER_ALG, \
.type = QEMU_OPT_STRING, \
.help = "Name of encryption cipher algorithm", \
}
#define BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE(prefix) \
{ \
.name = prefix BLOCK_CRYPTO_OPT_LUKS_CIPHER_MODE, \
.type = QEMU_OPT_STRING, \
.help = "Name of encryption cipher mode", \
}
#define BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG(prefix) \
{ \
.name = prefix BLOCK_CRYPTO_OPT_LUKS_IVGEN_ALG, \
.type = QEMU_OPT_STRING, \
.help = "Name of IV generator algorithm", \
}
#define BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG(prefix) \
{ \
.name = prefix BLOCK_CRYPTO_OPT_LUKS_IVGEN_HASH_ALG, \
.type = QEMU_OPT_STRING, \
.help = "Name of IV generator hash algorithm", \
}
#define BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG(prefix) \
{ \
.name = prefix BLOCK_CRYPTO_OPT_LUKS_HASH_ALG, \
.type = QEMU_OPT_STRING, \
.help = "Name of encryption hash algorithm", \
}
#define BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME(prefix) \
{ \
.name = prefix BLOCK_CRYPTO_OPT_LUKS_ITER_TIME, \
.type = QEMU_OPT_NUMBER, \
.help = "Time to spend in PBKDF in milliseconds", \
}
#define BLOCK_CRYPTO_OPT_DEF_LUKS_STATE(prefix) \
{ \
.name = prefix BLOCK_CRYPTO_OPT_LUKS_STATE, \
.type = QEMU_OPT_STRING, \
.help = "Select new state of affected keyslots (active/inactive)",\
}
#define BLOCK_CRYPTO_OPT_DEF_LUKS_KEYSLOT(prefix) \
{ \
.name = prefix BLOCK_CRYPTO_OPT_LUKS_KEYSLOT, \
.type = QEMU_OPT_NUMBER, \
.help = "Select a single keyslot to modify explicitly",\
}
#define BLOCK_CRYPTO_OPT_DEF_LUKS_OLD_SECRET(prefix) \
{ \
.name = prefix BLOCK_CRYPTO_OPT_LUKS_OLD_SECRET, \
.type = QEMU_OPT_STRING, \
.help = "Select all keyslots that match this password", \
}
#define BLOCK_CRYPTO_OPT_DEF_LUKS_NEW_SECRET(prefix) \
{ \
.name = prefix BLOCK_CRYPTO_OPT_LUKS_NEW_SECRET, \
.type = QEMU_OPT_STRING, \
.help = "New secret to set in the matching keyslots. " \
"Empty string to erase", \
}
QCryptoBlockCreateOptions *
block_crypto_create_opts_init(QDict *opts, Error **errp);
QCryptoBlockAmendOptions *
block_crypto_amend_opts_init(QDict *opts, Error **errp);
QCryptoBlockOpenOptions *
block_crypto_open_opts_init(QDict *opts, Error **errp);
#endif /* BLOCK_CRYPTO_H */